"The advantage that a lot of Open Source projects have is that they release the buggy code with a little tag that says "not for general use" and the users who want the newest features swallow the bugs for the latest Good Thing(tm).  I wish we could do the same thing, but when people pay for software they expect the latest features and stability all the time."

Are you suggesting that Microsoft does not have Beta test programs? There appears to be one for Longhorn, and I imagine it comes with the same kind of disclaimer.