different answers from diff folks. but generally, i've found ppl desire categorical spots because you can stay at one place for FOUR YEARS (dont have to pack up and leave after just one).
having said that...those ppl that say do a prelim and advanced in teh same city, prolly wouldnt care and would actually LOVE to be in a different hospital after their PGY1.
but yes, GENERALLY i think categoricals are more coveted