Hey, the device window of Mac version has been there for a few months. I am able to do drag and drop conversion (mostly FLAC to mpeg) straight to my iPod Classic, but the problem is that the folder structure isn't recognized by devices looking to read the database of an Apple device. The files are all there, but even the iPod itself doesn't know it! This problem seems to be something that Apple would need to help with, and that isn't gonna happen.
So, I have a pretty solid workaround in place. I have an old 160GB hard drive set up as a device in MC. I have a smart playlist defined in MC that I synchronize to the hard drive (with file conversion). I keep the contents of the external drive sync'ed to iTunes and use iTunes to sync to the iPod. It's an extra step, but I end up with a backup of what's on the iPod. Dig?
The one issue the MC could address to make this system tight is that the sync step from MC to external drive isn't properly updating files on the device. He knows about it, and says it's getting fixed soon.