I've been loving KOTOR2 so far, my only major problems with it, have been:
1. The frequent preoccupation of my main character, forcing me to use the other characters - I like to use my powerful character, and a lot of situations are very difficult without him, which really takes the fun out when I can't win, yet can't leave.
2. The similarly frequent (so far anyway) trapping me in one place. One of the things I loved about KOTOR1 was the ability to travel to whichever planet I wanted at almost any time in the game (until the end). In KOTOR2, I've been so far forced to stay on Telos, Dksun (twice now), Onderon, and Nar Shaadaa. (I've not had the chance to go anywhere else yet). I've found this rather frustrating.
Other than these, my thanks for a great game :D