Ultimate is weird because at times it wants to be satire, but at other times it wants to be a modernization ala USM and UXM. Those two things don't quite work together. Add an extra touch of Millar's over the top edginess and you get a book that just doesn't work, IMO.
I love Ultimate Spider-Man though. There are a few arcs near the end of the Peter Parker portion that aren't very good (Ultimate Deadpool and a chunk of the post-Ultimatum stuff), but for the most part, it's solid throughout. I read the whole thing in a marathon session a couple years ago up until the early Miles stuff (Which I then read as it was coming out).
Bendis stuff reads best this way, I feel. His Guardians run was an absolute slog trying to read month by month, but his Avengers was serviceable with a few moments of greatness read in a big marathon session.