I played this during the stress test weekend and found it to be pretty fun. I was more impressed with this beta than I was with d3's, granted d3's was severely limited in scope compared to path of exiles.
It just has alot of interesting features that I found myself scratching my head wondering why diablo hadn't done this yet.
To me this is what I liked about the game the most, the skill gems to me seem like the materia system from ff7, which I really enjoyed. I didn't play much of it since I had other things going on, but my buddy said you could level up those gems, and there is no penalty for removing them, I think you can even trade them to other people after you've leveled them.Skill Gem System -- A fun twist on Jewels from D2. Every usable skill in PoE comes from one of these gems. Socket it in your gear to be able to use it. Linked sockets allow you to throw in support gems to boost these skills too.
I've been going back and forth about purchasing beta access, a friend of mine said it was going into open beta in june, though for 10 bucks, I might just do it anyways to help support what seems like a great game.