Just something I think people need to keep in mind, especially those new to emulation:
Many of the errors and things I've read so far seems to remind me of some of the same things that have either existed forever on psx or aren't resolvable until Gingerbread comes out. They seemed to have made the optimizations to base architecture of android, in that, speeding up the draw-times was merely a side effect of doing thing like optimizing the way java code is processed. Gingerbread actually targets the 2d and 3d acceleration processes and shaders themselves which makes me excited simply because everything should get a whole lot faster than it sits now at froyo, it should be better for you all that like the Emus too.
If I remember correctly, way back in the 'day,' when psx emulation was young and voodoo 3dfx was still a recognizable name in graphics, all the ffs suffered from lag during their cut-scenes (especially ff8, basically the same run-stop-run, if it didn't just disintegrate into a thousand unrecognizable blocks of color) and on the world maps glitched, lagged, and locked up. None of this is new and without access to more efficient drawers 2d and 3d I doubt there's anything the maintainers of these emus can do until the google-verizon-motorola-htc-etc team(s) get the rev. to Gingerbread. I am not sure about the collision detection in xenogears though, that sounds more like something that is fixable within the emulator, but if it's not happening in many other games as well they'll have trouble pinning down what's wrong. Though low-3d redraw rates can lead to many collision detection issues, so it might get fixed after all.
Furthermore your phones are only going ever to be good at playing certain kinds of games, without having to constantly lug around some sort of wireless rf controller with you, the one on the screen just won't cut it for most games that require heavy use of all 10 keys. Many people it looks like are running into this problem in the comment section at the market place and don't seem to get that the developer is quite limited in helping them there.
\my 2 cents