I just finished it. I must say that I hate that it made me so sad at so many times, including all the final part. Just before the assault I was feeling...depressed because I thought we would just fail. I really don't remember any other videogame, ever, having such strong emotional impact on me at so many times except maybe FFVII and that was because I was a teenager, not a full grown adult or the BG2 endings (Minsc, Viconia romanced)
There's some details I didn't like (not many playable characters, no real exploration, etc.) but in general I think that it's an incredible ending to the trilogy. It has surprised me from the beginning to the end.
I remember, some years ago, how my brother was showing me the trailers for the first one and I was like "Bleh, I'm not into sci-fi with aliens and spaceships except Star Wars". Then one day I decided to try it and...got hooked. And now it's become one of my favourite games/sagas of all times.
I'm going to replay the last bit to see the other ending although I read that there's tons of additional endings.