Personally, I like Kamen's score the best. There's no x-men "march" in his score, but I think that his stuff was pretty subtle and personal, which fit the moments between Logan and Rogue perfectly. "Logan's sacrifice" is a fantastic scene, and the music is one of the reasons for it. The brotherhood scenes are done very well too. Like I said, it's not over the top or too serious, but feels just right.
I still like Ottman's X2 score, but I was dissapointed with some parts of it, and felt the strongest part was his X2 theme and the music for nightcrawler's attack. The music builds up when the x-men break through the spillway, but falls flat by quickly changing scenes and not showing the x-men plus mags marching through, which I hate- since Ottman was the editor as well, I blame him (plus, Cyke fans, he's the one responsible for cutting/editing down Cyclops vs. the guards/Deathstrike fight).
X3 has a good score- love the x-men march for that one and how prevalent it is whenever there's a little x-men mission going on (and I enjoy the wolvie vs. pheonix and jean grey vs. xavier stuff), but still felt that it wasn't quite as good as X1. The march is great when the x-men arrive at alcatraz, the first time we've seen a scene like that because of Ottman's cutting it out of X2.