Pretty stable for me, I've been on it exclusively since the previous nightly (18 september or so, haven't looked back). I only wish I could get bluetooth to work (both bluetooth ftp and bluetooth phone don't work for me).
Drakaz is working on the BT thingy, I guess he'll fix that before he releases beta3.
EDIT: however, even though I love the galaxy with GAOSP, I've been playing with a HTC Desire with 'official' 2.2 ROM and there's a world of difference between this and that. I still wish I'd waited a little longer and payed a little (!) more for the Desire.