I've played a whole lot of Path of Exile, but until recently, I'd only played through Diablo once just after launch and I knew the game had changed substantially since the expansion (Reaper of Souls) was released. That all changed a few weeks ago when I started playing in the recent "Season 3" event of Diablo 3. I leveled two new characters from scratch to max level and got them both geared out for the end-game content: greater rifts. What follows are my impressions of the two games now that I have some more context.
The two games have very similar feels once you have a character all set and ready to go. You click to move, you blow up massive numbers of enemies and you loot, loot, loot! One thing about Diablo, though, is that the game seems to be much more focused on the idea of using cooldowns. This exists in PoE, of course, but PoE doesn't stress cooldowns nearly as much. Diablo almost feels WoW-like in this respect: having cooldowns that you should really use every time they're up or close to.
Both games start off with complex interplay between abilities that cost resources to use and those that don't . PoE seems to get the player away from that more quickly, but by the end-game, you don't go around using abilities that you can't sustain in either game.
In a loot-based action RPG or "ARPG" the loot is always key. In both games, there is a dizzying array of common, uncommon, rare and epic loot. They each have different terminology (epic loot in PoE is in the form of uniques while Diablo calls them legendaries) but the idea is more or less the same. However, I will point out that PoE has much more focus on using rare items all the way to the very end-game. Rares are intended to be very powerful in PoE, but good rares are extremely hard to get due to the way the random loot system works (basically, you have the same odds of getting that perfect belt as you have of winning the lottery).
This makes PoE loot feel more relevant. Once you hit 70 in Diablo, you quickly start melting down every rare item you get without looking for crafting mats or selling them to vendors or just not picking them up at all. But in PoE, such items always bear a quick look at least to make sure they're not great.
One aspect of loot that's fascinating in PoE is the currency. But that gets into...
The Diablo crafting system feels clunky to me. It's very nice that you get starter set recipes that you can craft. That really makes sets seem more relevant to new players. I miss sets in PoE, but let's face, it, that game doesn't need more complexity.
But in Diablo, most of the end-game is focused on drops, not crafted items, and you only make trivial (but still relevant) changes to gear at the enchanter's station. Meanwhile there's PoE... the crafting system in PoE is unlike anything I've ever seen before. There's no gold or other currency that exists only to be currency. Instead, all of the "currency" items have random effects on gear. One currency type makes a normal item into a magic (uncommon) item. One currency type randomly shuffles the number of sockets on an item. Ultimately, end-game gear is all about crafting in PoE, and the amount of discussion and bragging that goes on around crafting actually rivals the gameplay. Seeing someone "Vaal" a rare is always a hold-your-breath moment and cries of "RIP!" are usually the result, when the item becomes useless.
Here is Diablo's biggest weakness. They basically removed trading in any meaningful way with the RoS expansion. Legendary items are account bound by default and can only be traded briefly with other players that were in your group when the item dropped. The Auction House feature was removed and trade channels are mostly dead.
Meanwhile trading is the heart of the community in PoE. Nearly everything is tradable and a complex system of in-game and out-of-game tools exist to facilitate the trading of gear. There's a whole metagame around getting enough currency through trading to get good leveling gear fast in the seasonal leagues in PoE, and understanding that metagame is essential if you're going for speed.
For evidence of the difference between the two, join the trade channel in PoE in Diablo. In Diablo there are a few messages every now and then. In PoE, accidentally typing "$" (which puts you in trade chat) means a torrent of spam as every item in the game is rapid-fire linked with prices; currency exchange rates; WTB requests; and price checks.
The two games are, of course, ARPGs. They live and die by their content, first and foremost, so how is it?
In Diablo, the story is much simpler and more coherent to the new player. It's very linear and though there's a lot of back-story, the player is right there in the thick of everything that is going on, so the new player will definitely follow along and "get it."
PoE's story is much more about the aftermath of huge events that the player was not there for. The rise and fall of multiple empires, the devastation of magic and religion gone awry, etc... you are thrown into a rich and complicated backstory that you only get pieces of. Your own story is secondary in many ways to what's already happened, and until the very end, you're really just mopping up the aftermath. This leads to PoE feeling less like a game in which the player has a major role (until the very end) and I think is the weakest part of the game. Once you do know the backstory, it's fascinating and well worth knowing about, but for a new player it's not as engaging as Diablo's lore.
Both games have a linear track of dungeons that you must complete to get to the end bosses. Diablo has more side-areas, but most of them are much thinner than PoE's. In PoE, there are side areas that are massive and have their own rich lore whereas most of the side areas in Diablo are small dungeons or simple cellars that the player quickly deals with as a diversion.
The event system in Diablo is really engaging as a leveling noob! I love it, and it really felt fun. PoE doesn't really have a lot of that. There are lots of mini-bosses and they feel more like unique and interesting parts of the world than Diablo's mini-bosses, but the lack of this sort of side event for the most part (there are a couple in PoE) is definitely a weakness.
End-game content is very different in the two games, but has a similar feel in some ways. In PoE, the end-game is "maps". Maps are a rare drop in any 60+ zone. They can be activated to create a one-time instance that has a higher chance to drop its own maps, which can be up to 3 levels higher than the map itself, and so the end game is a progression of higher and higher level maps, and eventually unique maps with extremely hard bosses.
In Diablo the first half of the end-game is the form of "rifts". Doing daily quest type "adventures" gets you rift shards and that allows you to open a rift that is similar to a random map in PoE. All rifts are scaled to the level of the player and to the difficulty setting, and mobs and the end-boss all drop excellent loot.
However, the twist in rifts is that you can't race to the boss and skip the "trash" like you can in most such games including PoE. This is actually a nice innovation. The end boss spawns when a progress bar is filled, and that part is filled by killing enemies. I like the feel of this, and it gives a much more dynamic feel to rifts.
The second part of the end-game is "greater rifts". These can only be done at max level and are unaffected by difficulty setting. In regular rifts you can get a trial stone. This is used to size up your power level by wiping out successive waves of mobs in a timed event with no loot. Once you complete that you get a greater rift stone which has a level. That level is the level of difficulty that the greater rift will have.
Greater rifts drop no loot until the end-boss, but are otherwise much like normal rifts except that they have to be completed within 15 minutes to get the opportunity to progress on to the next tier of greater rift. This makes for a fun and fast turnaround on running these events.
Overall, I prefer the Diablo model for ease of use and uniformity of experience, but PoE feels more like a coherent world with a progression through zones that you just won't see until you're good enough to get there. That kind of progression is important to me.
Both games look good. The art is excellent in both, though it's a little bit more polished, IMHO, in Diablo. PoE has a lot more detail in its art, but it doesn't always feel like it "pops" quite the same to me.
Bosses in both games are very dynamic looking and really feel threatening. The only thing that puts me off of Diablo bosses a bit is that they are sometimes played for adolescent humor (like the fart demon) but that's a matter of personal taste.
Zones in both games are highly variable and compelling. I've never enjoyed "looking" at zones all that much in ARPGs, but both games provide plenty to look at.
Customizing look and feel of characters is very different. In Diablo, you have limited choices for customizing gear coloration, and honestly the dye system is uninspired and relatively weak, but it exists. The transmog or skinning system is extensive and a big part of the game. The way you customize your look is definitely by making your gear look like other gear you've looted or unlocked the look of through achievements. There's no dying of gear in PoE, and all "skins" are purchased as microtransactions (see payment model, below) or earned via seasonal events. So PoE has less customization by far, but I'm not sorry to see the lack of the terrible dye feature. :-)
Diablo is a pay-once-to-play model. You pay for the base game and expansions. When they want more money to keep the lights on, they publish an expansion. That's pretty much it.
PoE is much more of a microtransaction-based free-to-play game and when I say free-to-play, I don't mean "mostly free, but you pay for the good stuff." I mean you play 100% of the game and all expansion content without paying a dime. There are no pay-only classes and there is no zone that you can't go to if you've never paid. 100% of the revenue for the game comes from selling extra bank space, custom looks for gear and abilities, non-combat pets and "supporter packs" that come with various perks that do not affect gameplay.
Most players will probably spend about the same amount of money on both games. $20 will get you a good set of additional storage space in PoE that most players will want, and over time, you'll probably do that at least a couple of times if not more. Plus you might find yourself wanting demonic wings for your character or whatever, so yes, you will spend money in both games, most likely, but in Diablo you will spend just to get basic features and you will have to do it in a pretty big up-front chunk.
Neither game requires a subscription, though, so the ongoing commitment is low to none.
I feel that PoE is the better designed game. I haven't gotten into mechanics because this article is already long, and any discussion of the PoE mechanics model is going to be huge if it does the game any justice, but suffice to say that the two games have very different learning curves. Diablo is more fun initially, but PoE is more challenging and rich in the long-term. And speaking of challenging, Diablo scales in one direction: bigger, tougher opponents. PoE scales in terms of the complexity of the creatures faced, the multi-faceted crafting choices, the toughness of creatures, the complex interplay of map and creature modifiers, etc. In short, PoE is hard and good players spend a long time adapting to its difficulty and complexity where Diablo is much more entertaining as a week or two of rapid-fire dungeon runs, but it lacks much depth or challenge other than just facing mobs with more health and more dps.
I will always love PoE, but I think I will definitely keep playing Diablo on and off as a change of pace and a nice "quickie" game.