1) I've tried FPSEce, and it gives pretty good performance, not quite asus speed, but up there with the best of them.
2) Don't think so, but some GapiDraw benchmarks seem a little slow.
3) Yep, most PPCs nowadays don't have this problem.
4) Not too bad, and better than the XDA I. The D-Pad is can be a bit fiddly, but the additional buttons for camera and recorder are handy.
5) It's a nice device! Go for it! Uninstall the majority of the rubbish custom apps put on by the telco, and it works much better.