I have been tested Gnome in deblet and in chroot and the chroot was faster. I dont know why, but gnome in deblet did not work, startind a single application like roxterm reboots tablet after 2 minutes lagging. Sometimes i chrooted to my deblet installation and ran apt-get from there because it was impossible to do it in booted debian. It might be my bad installation. And i know it was. I like more running debian apps in chroot, because i mostly fail installing deblet correctly. But KDE4 runs in chroot, and i dont think it is too slow, but it is still not very usable...