Hey, although new to this forum and just stumbled across this thread as I was also looking for what experts are saying about this RollBack Rx software. I have been using RollBack Rx, although not for a very long time and find it more than satisfactory. However, yes it does not GPT partitioning in the previous version. There is a new version being released for Windows 8 compatible and probably does support GPT partition. I have yet to try it out. Will let you all know soon. If anyone else interested, here is a post from their forum along with their pre-release of the new version : http://horizondatasys-forum.com/rollback-rx/23830-rollback-rx-v10-pre-release.html.
And I have previously said, I have yet to try it out. So if anyone is a ahead of me and knows whats going on with the new version, do let me know. Much Appreciated.