Just got an Asus EEE Pad Transformer last weekend. So after a little bit of use here is my reaction.
I don't think Apple has much to worry about at this point in time. From a hardware standpoint, the EEE pad is really nice. A beautiful screen, fast processor, and good battery life. However, I can't say the same for the Android operating system. With Android, every task seems to take 2 or 3 more clicks to do compared to the iPhone. In addition, the application interfaces lack consistency. Each new application is like a new puzzle. lol. This is not a good thing. No performance problems so far. The screen rotation is a little clunky, but mostly works.
Anyway, more to come on this subject.