I just finished rebuilding my system with the latest goodies to do virtualization -- I now have a quad-core processor with 12 gigs of memory and VT-d support. As part of that I just upgraded to Ubuntu 10.10, their latest and greatest. I've been using Fedora 13, Red Hat's latest and greatest, at work for the past month. My overall conclusion is... erm. Well. Fedora has its issues, but Ubuntu is getting to the point of utter opaqueness. For example, Ubuntu has a grand new grub system that generates elaborate boot menus. The only problem: Said elaborate boot menus are *wrong* for my system, they all say (hd2) where they should say (hd0). And the system that generates these elaborate boot menus is entirely opaque.... though at least I can go into the very elaborate grub.cnf file and manually edit it. Well, unless a software update has happened, at which point the elaborate boot menu generator subsystem runs again and whacks all your hd0's back to hd2s... even in entries that are old. Red Hat's grubby might be old and creaky, but at least it's never done *that* kind of silliness.
Now, granted, I am running rather unusual hardware in a far different configuration from what a desktop Linux user would want. If you want a desktop Linux system, I still believe Ubuntu is the best Linux you can put onto your system, I've run Ubuntu on the desktop for years and it serves well there. I especially like Ubuntu 10.10's ability to transparently encrypt your home directory similar to the way MacOS can, this will resolve a lot of issues with lost laptops and stolen data, this is an opaque subsystem but necessarily so. You can also put the proprietary Nvidia video drivers onto your system with a simple menu item, while with Fedora 13 you have to fight to put the proprietary driver onto the system (the GPL driver is loaded *in the initrd*, which makes it a PITA to get rid of). In short, if I were running Linux on the desktop, 10.10 is hard to beat. But for my purposes, doing virtualization research with KVM and VT-d, I'm wiping out Ubuntu in the morning and installing Fedora 13.