Just upgraded from stock JPO via Kies. It is 2.2.1 Quadrant 1250, It obviously connects with kies no problem, over the air updates still there it requires you to enter samsung account details?
So far.... Very Smooth, All A-Z in contacts, New Market App, Radio sounds better (not as flat) & my GPS (GPS Only) now pin points my house from my garden (before it had me a few houses away)
So far so good!