played in both the last 2 beta weekends. got a trooper to lvl21, and an imperial agent and inquisitor to lvl 7 each. seems like it's going to be a lot of fun.
is it like WoW? I suppose so. I haven't played that in years, but there are definitely similarities. You control a character in 3rd person view, you interact with the same world other players do. There's chat, and a toolbar at the bottom of the screen for your abilities. I mostly play City of Heroes for my MMO fix, but am looking forward to SWTOR. Picking uo my pre-ordered Collectors Edition this coming week.
Things I really like:
The storylines. It's very much a Mass Effect/Dragon Age/KOTOR type of roleplay, where you can have your character act to differing degrees of how you want them to. In one Flashpoint my team and I were given the option to save a bunch of guys, and have to do a lot more work, or let them all die for a quick fix to the situation we were in.
The companions. It's a great feeling when you get your first lackey...I mean, companion. It's a bit of extra help in combat (I had my trooper running about on Coruscant for a while handing in missions, and let my companion take care of the mobs I'd been aggro-ing whilst doing so) and you can send them off to do stuff for you. If you're miles away from a vendor and get full bags (as I often do in these types of game) I can send my companion off to sell my junk in a minute, rather than quick travelling or having to abandon the quest at hand for a 10minute run.
The quests. Sure, there are some "kill 10 womprats" type quests, or "pick up 10 collectables" but these tend to fall into a larger quest area, and even when they don't, you'll get some sad old codger, or hot girl explaining why you have to do it, and so it feels like you're doing it all for a reason other than levelling up. Anything above that level of intricacy is usually fun and story progressing, so you really do want to do it.
The setting. I'm a big Star Wars geek, I'll admit it freely, on this Transformer message board.

Walking around the different planets, ships and cantinas, it's a lot of fun, and there's been a really good job done on making the places feel Star Wars-y. A lot of it is little things, but it really all ties the thing together for me, and the atmosphere of the game is what will probably keep me playing for a while.
assembling a Neo-G1/TF:TM cast. Please PM if you have (or know of) the following at a reasonable price: Classics or Henkei Ratchet, Prowl, Astrotrain, Ramjet, Skywarp, Sunstreaker, Sideswipe, Blurr, Perceptor, Wheelie or 3rd Party Arcee, Springer, City Commander (and Ultra Magnus), Starscream (deluxe) Coronation add-on, or Spike and Daniel in their Exo-Suits.