I'm a total Sonic bitch, so I bought this one as soon as I saw Stu's news items. I don't think it's quite there yet, though. It's a pretty clumsy and rough conversion, I thought. It struggles at times, and where's the accelerometer controls?! Admittedly, they might not work in practice, but a simple left/right tilt control would get your fingers off the screen so you can see what's happening better.
I think it could be really slick, but Sega needs to give it more love yet. Roll on the updates.