Other 3D MMORPG's, you say? I'm a firm believer in "gameplay>graphics".
I have played great 3D MMO's (PlaneShift, Dream of Mirror Online was pretty fun during my brief stay), and terrible 3D ones (Runescape).
However, my favourites other than PlaneShift are Nowhere Else and Beyond and Kingdom of Loathing. They're both 2D, browser-based, one has sprites and the other has stickmen, but the games themselves are great and their chatrooms quite addicting (you even get some roleplay going on there sometimes, though on KoL it's sheer silliness and on NEaB it's a mix of that and a powermoding contest).
As for what I liked/hated about the 3D ones, I'll say this:
Runescape: Everyone knows it's terrible. Probably the most redundant game on the 'net. Takes ages to level, and somehow people keep coming back to it. You're "encouraged" to become a paying member with every update they make, as well as every other NPC interaction in-game.
Only thing I liked about it in my brief stay was talking to a certain friend while I played and joking around about the in-game things.
Dream of Mirror Online: Much better experience. You might not have heard of this one; it's a little Korean game, I think, though they have an English server. Very cutesy, anime graphics (I'm a sucker for cutesy things), and they had a handful of different races - my favourites being the anthropomorphic cats and the slyphs. I loved how the slyphs got to float around, flying was a skill you could train in, and there were lots of NPC quests. The locations were quite pretty, too.
Some things I didn't like about the game were that the battle system was pretty confusing, and they had this little system where sometimes, you'd "fall in love at first sight" with another character at random, as decided by the system (it was cute at first, but then it got annoying). It also lagged quite a bit, but that's because I was playing it on my old, crappy PC.