I tested this 550 a few hours today and so far I haven't found any defects.
It unlocked right away without a hitch. I bought it at Micro Center for $90 which IMO makes this deal hard to beat.
The NB @2800+ runs Cinebench 10 64-bit.

4410MHz validation link
http://valid.canardpc.com/show_oc.php?id=726155