On the technical side, it was superb. Aside from what others have mentioned, the sound design was incredible. The phasers, particularly the hand guns, were very tough. Lots of strength in the beams. The sound effects were great in general.
I liked the overall feeling of family among the crew. Riker leaving wasn't just an old friend leaving the job. He was the oldest son moving out on his own with his new bride. Data, the middle son, dies and the house was gutted by disaster, but they're repairing and moving on.
The performances were all great, Jerry Goldsmith's penultimate score before his passing was excellent; the official soundtrack CD does not do it justice and neither does the epic butchering of the end credit piece. For his career and his life to end pretty much on that end credits suite is fitting. It's a beautiful send off (Looney Tunes: Back in Action was his true "last" score, but Nemesis was his final "dramatic" score). I miss Mr. Goldsmith's contributions to motion pictures a great deal.
And honestly, I liked the whole atmosphere and the fact that it didn't take place on an Earth type planet inhabited by white people in clothing from the Land's End catalogue.
I love Nemesis, always have.