I dropped Ultimate Comics X-Men due to the ongoing lagging Stryker arc. Just not interested at all. They're putting the team back together under Kitty's leadership right? That was what was starting to happen at least when I dropped it.
Ultimate Comics Spider-Man is pure awesomeness right now. Bendis is like any other writer when they're excited and passionate about a character, it shows in spades. It is typical Bendis pacing and structure, but he is seriously knocking it out of the ball park with Miles Morales and his supporting cast. Sara Pichelli's art work is stellar. A worthy successor to Mark Bagley. I felt Stuart Immonen's style was too cartoonish for the book.
Ultimate Comics Ultimates is the serious stuff...Hickman left, but the current writer (who's name escapes me) is continuing his story. Ultimate Captain America just returned back from his self imposed exile and things are gonna pick up!
I'm kind of interested in Ultimate Iron Man Vs Mandarin...and Marvel has no plans for an Ultimate Comics Fantastic Four right now for obvious reasons.