Seriously, it's a joke. First off, these people were given PCs to use. Pre-selected PCs, that were selected by Microsoft. It's not as if it's difficult for MS employees to simply run a few tests on the hardware to make sure everything works perfectly on that one machine. Part of the merit of an OS is the ability to be used on various pieces of hardware, including the one that you have before you even make the decision to upgrade. Having to buy a new computer just to use the damn thing plays a huge role in the quality and usability of the system. I'm certain next to nobody would use Ubuntu if they had to buy a new PC for every release, no matter how awesome the improvements were.
Secondly, how long were these people given to mess around on these things? The fact that they're on pre-selected PCs makes a huge difference as well. This people on it didn't have any of the comforts or programs that they're used to having, and it's impossible to form a good opinion on a system based upon just an hour or so (granted, I haven't even watched the video yet, so maybe my rant is slightly ironic) of messing around. To fully understand all of a system's pros and cons, you have to take it home, install it on your PC, and try to do your normal, everyday things with it for a while. It's then that the little quips about the systems begin to make themselves clear and annoy you, and when the giant gaping flaws make your life miserable. If these people just sat around and mashed buttons for an hour, of course they wouldn't have come across Vista's flaws, just as mashing buttons for an hour on the live CD of Ubuntu Hardy won't let you see all of its flaws either.
Lastly, if I was given a temporary PC to try out, I wouldn't go ahead and install all of my regular programs, visit my regular sites, etc. (especially knowing that the PC belongs to Microsoft) I wouldn't actually try to use it, I'd probably just use the included tools (which Microsoft has the capability to guarantee will work perfectly) and try to make the best opinion that I can. Well, you can't really make a good opinion on a system, again, unless you actually try to use it just as you would use your computer normally.
Honestly, it's this kind of BS that gives Microsoft their bad reputation in the first place, haven't they learned anything? ;/