XA2+SF user since 1 year.
Very happy.
Still not as rich and complete as the N900 but much more presentproof.
Modest use though (but with SF mail app 
):
Phone, sms, mms, camera, mail, fernschreiber, whisperfish, terminal, some web surfing, Android present but almost not used, unplayer, pure maps, fahrplan.
Since some days, messages don’t want to start sometimes.