I'm using it. Technically, it's fantastic, far superior to the clunky Netflix app. Quality, even over 3G, is terrific on both iPhone and iPad. The major hurdle is not technical but must have to do with the "deals" in place for delivering mobile content. When I log in on my laptop, there are a ton more shows than when I log in on my mobile devices, that's a problem. I don't mind $10 a month, I don't mind the short form ads, but I DO mind missing a bunch of content, when, in theory, I'm paying for everything on hulu "plus" additional content not on the free site.
All that said, there are still some glitches. I don't get the whining about paying $10, that's how much one movie ticket costs and it has 15 minutes of "ads" at the beginning of it.
If DVDs were free for a year, then they decided it wasn't working so they needed to charge $2, many people would freak out. This isn't hulu, it's the writers, actors, producers, etc. who are demanding (rightfully so) more monetization of their creative property.
ash =o)