In reply to the OP - yes, 1.22 NA is stable. Much more stable than any other 1.2x series of firmware.
In reply to 420, it's pretty simple - the items bought from stores / online retailers, and especially those with Rev A hardware, seem to have issues independent of the firmware used (case in point, I purchased mine in Jan '09, and had nothing but issues, until I RMA'd it in Oct or Nov - and since then it has been smooth sailing).
Stop trying to fight with it - learn from my fighting of 9 months! and RMA it now.