personally I've enjoyed POE, although I haven't had as much time to play it recently, I did try it a year ago during a closed beta and again recently during open. It has some pretty fun pvp modes/ladders they added since then which unfortunately is lacking in D3. The game is meant to be pretty dark, gritty looking an ode to D2 I suppose as the developers put it.
As far as items go, it is hard to compare with something like D3 in which it is a game entirely based on chance with little the player can do to put the odds in their favor aside from running harder levels of inferno mode which require more gear to begin with anyways so it kind of ends up being cyclical. With POE you can turn a crappy/ok item into something pretty good with the usage of sockets, and special items that can add sockets to any gear. I could go into great detail about socketing strategies to get the most out of your items but I'm sure you could easily google that if you were interested in getting the most out of your experience.
The same can be said with the skill tree if you know what you are doing, although that is fairly complex in itself.
For the average/starting player the game is extremely daunting unless you really study up on the game because there is little to no guidance in-game in regards to what the player needs to do to be achieving maximum DPS etc. It is a great game when it comes to customizing skills/items, no two characters will ever be alike, unlike D3 which has 1-2 builds/item sets that every single class uses and needs to go for to hit their max DPS. So as far as replay-ability goes there is a lot of future potential to the game for those that like to tinker around with their character trying something new.