I tried it on my Galaxy S last night, and it worked reasonably well, but has a few issues.
Firstly, it lacks full mouse support (I was playing BattleChess on it, but you cannot select the right mouse button at all for the menu), and it only has an overlay for the joystick.
The mouse pointer is way out of position from where you press, but you can work around it on the most part. It only supports adf, so no IPF images or DMS disk images.
It lacks ALT, CTRL and Amiga keys, so anything needing those and you have problem. The onscreen keyboard also takes up the entire screen when selected, so you cannot see what you are typing. Ideally, you'd be wanting to play a game that needs joystick support only.
Frame rates (with sound) were fine considering it is running on a mobile phone.