RR4 is now known as Sabayon, and since it's based on Gentoo, I had to give it a try. It's currently in internal beta, but you can grab it later this month.
After playing around with it for a while, I find it has a ton of potential, although it's rather bloated in terms of software included. While Gentoo lets you start as a base and build up, Sabayon throws a bunch at you. This will be fixed nearer to it's launch though, I'm told.
Here are some screenshots of the RC2 for those interested. Note the versions... very up to date software!
Overall, I can say the distro has some awesome hardware detection, and activates NVIDIA, WiFi [Depending] and Bluetooth even off the Live DVD. Installation took around 90 minutes and used 7GB of HDD space. I am hoping to see them add package groups during the install before release though, because it really is far too bloated for my liking.
I should also note that Sabayon supports XGL also... even off the Live DVD. Great Gentoo based distro overall. With some tweaks, it could be superb.