Archlinux is flexible and customizable. You can either use pacman to install the binary package instantly, or would rather compile the source package via abs (you cant miss the yaourt tool!).

However, the shortcoming of pkgbuild is lack of USE flag control compared with Gentoo. You’d have to modify the pkgbuild file to meet your own needs.

In aggregate, I would highly recommend Archlinux for these reasons below:

1. You’re lazy but squeamish, need a clean system rather than finding a lot of things you dont need already installed in your system
2. Sometimes you’d like to build the package from source without getting your system dirty
3. Your comp is too old to compile everything, but you need a linux environment as soon as possible.