If you are thinking of moving to 5.2.1, I encourage you to think carefully.
Our encounter (albiet brief) with 5.2.1 was pretty disasterous too. I'm camped at 5.1.2P2 and have no reason to move. Except for the occasional 5.2.1 floppy boot for the fiber channel diagnostics. ;-)
One day, i'd really like to see NetApp move to a user patchable OS. Anyone else?
Graham