I've got to say that, unlke many apparently (?), I never hated the other UT games. They all had a different feel. Luckily. I wouldn't have wanted a carbon copy of the first. UT2003 felt very strange the first times I played it, but it sort of grew on me. I liked the content the community pumped out for both UT2003 and UT2004. Favourites of mines were the Angelheart maps. I tried UT3 for a while, I think it almost lasted a year.. off and on. But it didn't really work. Nevertheless, I didn't dislike it really.
As for music, it's hard to decide. UT 1 had an amazing soundtrack, but the following games were certainly up to par. Imo.