But enough of that. It looks like a release candidate is planned which presumably should bridge the gap from beta to RTM. No issues then!
MS has no plans to makes things more difficult and hurt 7's launch, that is why a release candidate is planned in the month of august or prior to bridge the gap so to speak.
But, we all know how things change..... Being part of MSDN I cant tell you how much changes from day to day.. Therefore, even though R1 is stated to be out to bridge the gap, its always best to be prepared for the worst and utilize a separate partition for a beta release.