>>10
No. Just the DEFAULT Desktop is different. You can still install Gnome on Kubuntu and KDE on Ubuntu.
>>3
Linux Snobs don't look down on it, because it is so easy to install and handle. There are other reasons:
1. Ubuntu prevents the user to learn what to do when X fails
2. Ubuntu's number of packages in their main-repository is small (compared to Debian, SuSE, etc.)
3. The developers claim that they made the best distro, intentionally not mentioning that they just take the preconfigured packages from Debian. They just don't take all of them, and change the Style of Gnome and KDE so that they look quite unique.
4. They take, but do not give - they always claim, that they give all changes they make back, but that's just not the case. The nly real thing they developed was Upstart. Unfortunately it doesn't really make a difference if you use Upstart or the "old" SysVinit.
Ubuntu is a leech. Have fun with it, Ubuntu-users.
BUT FUCKING STOP TO SAY THAT YOUR DISTRO IS BETTER THAN OTHERS. PROTIP: IT ISN'T!