How exactly does google android function on the N810?

Does it supplant the entire image, or is it a user-space stack replacement that runs on the existing kernel & modules?

I'm super interested in it, but obviously it's still a bit young. It would be nice if I could run both android and maemo for the first while until a clear winner is determined.

Anyone have some thoughts and suggestions?

My N810 should be arriving in the next three or four days!!