Centaur or Chorus would be the equal to Ultegra, except that both Campy groups are 10sp. Find bikes with both and ride them along with Ultegra and see which you like best. Make sure that you ride triples o all the groups, since the shift quality with a triple is different due to the long cage derailleur and wider span on the front derailleur. I am a BIG Campy fan, but YMMV.