It's a pretty fun single-player MMO experience.

I stopped leveling my Jedi Consular around level 18, and have been leveling a Gunslinger Smuggler, now in the mid-twenties. But the game simply has not gripped me. Part of it is probably that I simply find the IP rather boring. To give you a contrast though, my boyfriend is a complete Star Wars geek and he is enjoying the game immensely, has a trooper up to level 48, doing tons of PvP, etc., and says he would never go back to WoW.
The VO, the amount of instancing, how they handle group convos is all interesting. The "orange" items that can be modded and used for really long times was an interesting choice. The attention to individual class story liness was good - something Bioware does well.
I get bored with the giant boring spaces that I have to run through a lot. (The person who designed Coruscant should be slapped for putting miles of extra hallways in both combat and non-combat place used at a level where people do not even have their running speedboost yet.) I don't find the art design to my taste, though people who like star wars in general seem to like it a lot.