I liked Aion a lot. It was very graphically appealing. I loved the cut scenes! I made and remade a lot of characters; char creation was very fun. I liked the players. Yeah, there were one or two jerks, but most everyone was enthusiastic and friendly. Such a nice game it's going free to play will probably put a lot of junky f2p's out of business.
Reason I left: Furniture crafting. Very simply, I could buy cheap eccentric furnishings from an npc (in the housing area). When I crafted furniture, which I spent hours and days on and cost me lots, I got crate looking ugly stuff that I could not give away let alone sell on AH. I was so disappointed I left.
Other things I found disheartening. The PvP, or should I say Realm vs. Realm. Just not my cup of tea.