?.... Is US anime really a term? I thought anime was unique to Japan. And us anime wanna-be's would have to settle for "Anime Style". *shrugs*
And I dunno, I have seen some pretty good stuff come from the US. The drawing style may lack some originality (being that it seems very influenced by eastern styles). But I have seen some American animated series, with quite interesting story lines, and some are visually pleasing to boot.
With that said... I do prefer Japanese anime. I think story lines and artistic styles derived form Japan often seem to have a certain rawness, I think cultural influence must play a part. Because Americans just can't seem to reproduce it.