One thing that has kept me on Ubuntu family distros is font rendering. Ubuntu's patches for freetype, cairo, xft, etc are quite simply requirements for me for a desktop Linux.
Some distros have these by way of some guy maintaining his own set of patched packages. I have always been reluctant to rely on these.
I was thrilled when Linux Mint came out with Linux Mint Debian Edition, which is Debian + these font patches + some other Mint-y friendliness (but still mostly Debian).
The fact that Arch maintains the *-ubuntu family of patched packages means I just might consider using it, too.