Been doing some experimentation to see about a switch of main distro. Here are my findings. If I could be bothered I'd link stuff, but I'm sure you can search yourself.
Lubuntu - that's what I'm working on here, 13.04 to be precise (or raring!). Quick and clean, I like it. But not likely to be my longterm choice
Kubuntu 12.04 - main desktop, I like KDE again, it appears to have speeded up. Ubuntu variation gives a solid base but I am worried about some of the longterm direction.
openSUSE - nice, but a bit slow and large. May as well use Kubuntu, in a way
Fuduntu - No. Not now. Hate Gnome 2, anyway. Unconvinced about choice of Consort for FuSE, too
AntiX - nice, but support may be a bit variable as a bit niche. Also haven't got the will to endlessly edit config files, although I do recognise that this is the best way to get it right for YOU
Toorox - I like the idea, but the installer fails in a VM so I need to be persuaded
Gentoo - digital masochism
CentOS - really nice, but possibly not as an everyday desktop distro
Kali - would convince me more if the installer had worked in a VM. May try again, but not sure I have the enthusiasm for another lengthy installation session only to find a failure
Manjaro - I like this a lot, going to try the KDE and LXDE variants in VMs. Community are really nice folk, too, plus it rolls and has Arch behind it.
Salix - nice, but didn't excite me
Mageia - not for me, sorry
openMandriva - nothing to see here, move along
BSD - hmm, including PCBSD et al just not doing it for me
Fedora - have you tried that installer?! No.
Ubuntu - I actually don't mind Unity, but as above I worry about where they are headed. They are aiming at consumer devices having not quite, IMHO, made serious inroads into the server market (unlike RedHat ergo CentOS)
In short, once I've tried Manjaro for a bit I'll be in a better position to pick. I'll probably still keep this Lubuntu/AntiX machine, and so forth, but the migration will probably kick off in about a month's time. Unless I change my mind. Again.