Eh, I disagree -- OHBs are awesome grounds for getting -better- at the prog you work with, but trying something out for the first time in OHBland is folly because you're going to spend the majority of the time clunking around trying to learn it in a hurry. That sort of stress is the quickest way to muck up my own creative brain, and I suspect I'm far from the only one here.
Now -majors-, on the other hand, are perfect grounds for mucking about with a new kit, and sunvox indeed rocks, so go out and make some Spring Tracks IV voxes, folks! :D
[EDIT] To clarify something, for folks that -are- comfortable learning a new tool in a short timespan, more power to you. But some of us aren't going to be able to do that no matter how we try. OHBs are hard enough as-is. :P