Yeah, like Zenosincks and jonmcc3 said, if you like KDE, then go for another distro, however if GNOME is what you want, then just stick with Ubuntu, and you'll be fine.
Besides the desktop environment, there's also the different applications, that come installed by default. You can run GTK applications on KDE and vice versa, but they just don't look very visually integrated with the rest of the system.
I personally prefer GNOME, but I'm not going to elaborate on why.