So no biggies then. Just 3 days and a half of your time and 1500$. Almost a non-event.
No, once I was satisfied that Crucial had actually admitted the cause of the problem as a software bug (in handling SMART values), and that the update worked for all normal people, I elected to get someone local to do it. Another plus was the support for both AHCI and IDE. Working around users, it only took about half a day (with me helping by running backups remotely and supervising over the phone), so pretty much best case scenario.
I estimated that we had 8 days to go before the first of the drives went belly up. So I really didn't want to put it off for another week.
With the benefit of hindsight, I'd consider taking a risk on multiple workstations without any new data and just skip the backup. So you could really rip through quite a few non-Marvell machines with that method: insert CD, reboot, choose drive, remove CD, reboot. Of course, explaining to the one person in 50 with a bricked drive that they'll have to wait for a rebuild ...
Having said all that, the stress took a couple of years off my life, and I don't have any cost recovery for all my time on this. So f*ck you, Crucial.