Yeah... that's been my past experience with USB docks, at least any with more than one slot. I've never had great luck with them. "Can recover from power outage without being touched" is a key requirement for my NAS so I'll give that one a pass and stick with my "SATA drives directly attached to a SAS controller" strategy for now. Thanks for the reply.
As for the 24/7 use, yeah so be it. The I in RAID stands for Inexpensive. If they fail after 10 years at 24/7, so be it. I have drive level redundancy and frequent offsite backups of anything critical.