Nah, there's work arounds for the errors you get during install. You have to do the prep work on R1 for example.
Should be fixed I would have thought, although there's rumors that it won't be supported at all. That would suck monkey. It's probably related to the Powershell funkery, R2 is PS2 isn't it? 2k7 is PS1?
I tell you what though, SP2 for 2007 is a world of pain if you don't have the relevant rights etc. during install. Error after error. If I had any hair I'd have pulled it out already.