I just finished it, and I thought it was simply brilliant.
After you get done with Peragus and Telos at the beginning, the story gets moving and gets very interesting.
I thought the plot twist of the game was pretty good, not near the caliber of KOTOR1, but pretty good still.
The whole story? Very good, I think the story is as good as KOTOR1.
Characters? The characters are very well done, but there isn't as good of character development and interesting characters like there were in KOTOR1.
The game as a whole, I think it's bigger than KOTOR1, and there is a lot more that was put into this one, especially how you can customize all of the weapons and armor, and create items you are in need of. I also like how you can influence your characters and align them to whatever you are.
BTW, I've heard that you can turn Atton into a Jedi... Is this true?