It's still misbehaving a little. One of the drives is running very hot (particularly during RAID resyncs). Still, it's responding normally. I'm going to have to look into sending the drive in for warranty replacement.
Even with the problems, I'm still happy with the device. No data was lost, just some time fiddling with the unit to get it back up and running. The automatic backups to an attached USB drive worked beautifully.
The 5100c is almost reinstalled. It doesn't have Corel installed yet, but just about everything else we use is back on it.
I'm experimenting with a few new tricks for managing my media library. I like storing my music on the ReadyNAS because I can stream it to other machines easily (and I like the redundancy and backup capability). I don't like storing my music on the ReadyNAS because it slows down iTunes and my library tools. Since the 5100c has a bucket of storage now, I'm setting up SyncToy to keep the library in both places. Yeah, I could use rsync. Well, I tried, and there's a chance that some of the things I tried with rsync may have been what triggered the failure on the ReadyNAS.