Hickman's THE ULTIMATES #2 is one of the best comics I've read all year. Bendis' ULTIMATE SPIDER-MAN #2 was similarly great (as well as the scene between Miles and his uncle in Issue 1). Spencer's ULTIMATE X-MEN hooked me from the start; only Hickman's Hawkeye mini seems to be the weak link so far, though I really only disliked its second issue. ULTIMATE FALLOUT didn't do much of anything for me, but I think most of the new post-relaunch books are proving to be pretty good so far. Give it more time, though; ask again after each first arc is through.
Exactly. Hickman's The Ultimates and Bendis' USM are both very strong (at least right now, early on). Hawkeye isn't really interesting, and the story serves better as a side story to the events in Hickman's Ultimates than it does on its own. Ultimate X-Men is only one issue in, but it shows promise, especially since its a drastically different X-Men book than any of the 616 versions (its feels very much like a set-up for a Days of Future Past type dystopian future).
But yeah, overall, the titles are quite good. Even the weak link, Ult. Hawkeye, is better than a lot of the Ultimate titles put out post-Ultimatum, much better, just not as strong as the other three new titles.
EDIT:
CBR gave USM #3 a 5 star review, and the first two issues were scored 5 and 4 stars respectively.
Buy yeah, USM has been really good so far, not only because Bendis is on his game, but Pichelli's art is really vibrant and clean, and does a good job with both the action and the more emotional moments.