Just based on specifications, I see no reason to choose the Amy over the micro.
Unless there's a significant difference in price, which there might be since I'm in Canada and not Europe, I don't see the advantage.
Being able to use vanilla SDRAM in the Amy is nice, but AFAIK, all eyetech boards ship with memory anyway, so it's a moot point.
On a side note, I've started messing around with AROS on an old x86 machine that I had laying around.
After the initial struggle to get the native port installed onto the HD, I'm having a blast with it, and I could see this thing keeping me busy until OS4 hits.