Here's a bit of a warning ... Last week I uninstalled VS2010 as it was running alongside VS2012 and it was of no use any more. Tonight I launch SSMS 2012 and it says required components are missing and tells me to reinstall. Web searches produce lots of hits, and suggestions about deleting registry keys are worthless. I ran the SSMS 2012 installer exe again and picked "Repair". This miraculously made it work again.
I also noticed that the registry keys under SSMS have dozens of references to VS2010 folders. I changed some of the more obvious ones to point to equivalent VS2012 folders, which fixed some other warning popups that I was getting. So basically there is an unholy tangle of dependencies between SSMS and VS versions more subtle than I suspected, so be careful. I look forward to building a brand new machine next Xmas to clear all of the detritus out. I'm always irritated by the way many "big" products don't uninstall so easily or so cleanly, leaving fragments all over the place. Greg K