[Scott Fraser]

AFAIK, external hard drives are now pretty thoroughly commoditized. They
even interchange between PCs and Macs pretty transparently.

Sometimes. There's some PC format (not fat32) which will hang OSX.

I favor buying them from the main drive manufacturers, like Seagate
and Western Digital.

However, there is a Seagate model, (& I can't be specific because
there is no model number on the case,) which automatically goes into
sleep/spin down mode after a certain amount of non-activity. It's
usually about the amount of time it takes to set up an additional
microphone, walk back to the control & hit record. Then, you wait, &
wait, & wait for the spinning beach ball. It takes 10 or 15 seconds to
wake up. It's a big pain in the ass & I would happily ****can this
drive if it weren't the property of my best client. Caveat emptor.
Make sure the drive you buy doesn't take naps on its own initiative.

Scott Fraser