Also, there are performance-related aspects where distros do vary. For example, recently I compared the boot times of a few major distros (measured from GRUB to the display manager):
Sabayon (OpenRC): 31.6s
Sabayon (OpenRC parallel): 29.8s
Sabayon (systemd): 26.8s
Given the difference between the best and worst case is 10 sec, or ~50%, that would certainly make a noticeable difference. (Although Debian is probably faster only because it just had KDE installed, with none of the useful services the others ship with.)
Something like this would be very useful to have in a multi-way comparison, since it would make a real difference to people.
I'm also a recent convert to Sabayon from Debian (switched just last week). Gentoo really does have some nice aspects (e.g. eselect), once get past/around the source-based packages. It's also a lot more stable than I expected - so far I've only had to deal with one bug (the screen locking issue in KDE 4.10).I'm personally using Sabayon since Debian has become quite convoluted lately with all the half functioning user land packages. systemd is being developed too quickly for Debian to keep up so there's just too much breakages and rust collecting. Being familiar with Gentoo from the server, I figured a binary derivative should be fine. And it did.