Well it looks like I'm stuck for now...
I tried Jettison to see if it would help my OWC Mercury elite pro external drives to spin down once ejected but no luck. I assume sleepwatcher would only do the same thing since their purpose is one and the same (except Jettison is WAY more user friendly) so those to options are out for me.
kdeemer....how did you know your WD drives were the "green" ones??? I wonder if that's what I have? They went to sleep fine before the Mavericks upgrade.
Cornel....what type of external drive do you have that the recent mavericks upgrade fixed your problem?
One of my drives is for all our media (movies, photos etc.) and the other is our time machine backup drive for everything, so USB would really slow things down....because my imac is from 2007, it doesn't have USB3 ports at all.
I'm in too deep with Mavericks and several updated apps that only run on mavericks, to try to switch to Mountain Lion at this point. So mavericks is now the "crazy neighbor next door" I have to live with.
When I called OWC to find out what solutions they would recommend, they said this was a major issue that apple is fully aware of and all we can do is wait for a bug fix at some point. He insisted that it's fine for the drives to spin all the time and won't affect the life of the drive, but I don't believe that. My drives get very hot and my computer is on 16-18hrs each day.
There has to be a hack to fix this issue....anyone????