I have been using KDE distros for a while: Kubuntu, OpenSuse 11.2, 11.3. I once tried Ubuntu GNome and I didn't like it; it was not as colorful or as playful as KDE. I have been using Mint 9 KDE for about 3 months now on my desktop ( 3GB RAM, 480 GB HD, Intel Motherboard, Pentium Dual Core 2 Duo ); I have been happy since it has been the more stable, friendly and polished KDE distro I have tested.
Yesterday I created a partition to test Mint 10 Gnome. I was pleasantly surprised: the interface was much more polished than Mint 9 KDE; I had the general impression of faster speed and better image quality. Software like OpenOffice loads much faster... It seems simpler than KDE, and a bit more friendly. Windows effects are smother and more refined.
I have been reading some reviews on Mint 10 KDE... as being ok, yet slower than 9 KDE. Maybe I'll move to Mint 10 Gnome for a while...In synthesis (for me): faster, seems solid, more refined and friendly.