Stuart always strikes me as being kind of cartoony/anime-ish, but that kind of high-energy style works better for USM than, say, Ultimates (with what's-his-name replacement). If he isn't a lock, a good alternate choice would be the gents who worked on the USM annuals (I could barely tell the difference between them and Bagley).
But, a big, BIG point in Stuart's favor is that (like Bagley) he isn't consistently late. Having "prestige" artists one a project (like Civil War, or NYX, or Ultimates...) just leads to disaster. Sometimes a competent artist who delivers what you want is better than the next comic michael-mo-langelo.
