For me, it took me a while in deciding whether or not I would like KOTOR and so after much deliberation I went out and bought it, and had a great time playing it. The characters are varied and interesting, the locales are beautiful to wander in. It's also a pretty big game with lots of story, quests and epic battles.
But then some months later I got KOTOR 2 and that one didn't hook me at all. I got past the first part on the space station but then all of a sudden the story became less and less interesting and I finally gave up on it. Maybe I had a case of KOTOR overkill, especially after playing the first game quite intensively. Or the game just didn't feel as polished and absorbing as the original. That just my opinion really...
I found something interesting recently and this might be for the people that thought KOTOR2 felt unfishished and rushed. It's called the KOTOR2 Restoration Project and could make a flawed game into a sublime one. Here's the link:
http://www.team-gizka.org/index.html
Jam it back in, in the dark.