Ok, i have a couple questions about open source cloud computing services or software. I'm trying to make a decision on whether to go with open source software and pay x amount to technicians or go with a turn key service already in place like 3terra. I think I'll save money over time if I go with open source, but will probably have more headaches along the way "naturally"

. But for the sake of this thread, I'll stick with the open source direction. So here are my questions.
1. Which open source software should I go with? i've been looking into "www.openqrm.com" and "www.eucalyptus.com". Both only provide support on linux machines as far as I can tell. Does anyone here have experience with either of these in a real world or even test environment that can shed some light on them for me? I'm mainly looking for stability and ease of use and management.
2. Are there any other open source cloud software out there that supports both windows and linux machines in the same grid or that are simply better than the 2 above?
Thanks!