I have been a Gentoo user for a while but lately gave it up and tried ArchLinux.
The reason was that packages sometimes break and all the compiling and the lengthy install process.
What I really really like about gentoo is the package management. For each package you can choose whether you want the stable (extensively tested) or the unstable (you shouldn't take this unstable not very literally; ~x86) version.
Further, it is possible for each package to determine which specific version you want. Or if a version does not work, you can just mask it and it will go back to the old version.
If there is a newer version (than the masked one) it will be installed.
Now, Sabayon Linux is based on Gentoo.
But it uses an overlay (package repository that the Sabayon team have made available).
Also it has a very easy and fast installation. It let's you choose between a desktop (KDE, Gnome, Fluxbox) install and for example a server (core install).
Sabayon has announced Enthropy, which is a package manager which uses precompiled packages. Yes, indeed this has some disadvantages for optimizing all packages for your architecture but it saves you loads of time and it will still be possible to compile the packages.
So be ready for some post about Sabayon Linux