I dunno about Kubuntu 13.04, but 12.10 is a distro I have a lot of time for. I quite liked 12.04, but 12.10 has so far for me been one of the best distros I've ever used. KDE has grown into its skin very nicely now, and fulfils its promise. It's mature and complete, and extremely stable, and not a moment too soon.
Sad that Ubuntu 12.10 hasn't turned out so well, but clearly the OS underpinnings are solid, as the spin offs and community respins from it have so far proved fantastic.