I've never really gotten into Ulta, i've browsed the site a few times and never really seen where it's that amazing seems to me they are mainly a drug store makeup place, seem to have more of that than anything else, we don't have any around here for me to go to and really get a feel for it.
Sephora on the other hand, i LOVE and i'm totally obsessed with. They deal with only mid the high end brands and thats what i love, plus they have so many cosmetic brand choices. Everytime i go there or log onto the site (i check it out daily) i find 10 things i MUST have.