First of all, get this:
http://www.vmware.com/products/player/ Yes you have to register, but it's not a big deal. Enter fake information (
www.mailinator.com ftw) if you like. Then you don't have to worry about re-installs or anything. Virtual machines ftw!
As for my impressions, they ditched the start menu and didn't give a good replacement. If anything, this is a step back to 3.1 days where you'll have folders of icons on the desktop, and organize that way. I like the new tablet-centric interface, and think it'll be great for that, as well as for frequently-used applications, but they still need a "central repository" which was the start menu. Eliminating that is a mistake that will bite them hard IMO. Other than that, it's fine. I wish there were more builtin games though. I'll be pulling minesweeper at the least from win7.
From a developer perspective, I like the 2010 UI better (not greyscale) but I actually really like C++/CX aka metro style libraries. C++/CLI I never liked as it was still on .NET, but C++/CX actually compiles down to actual machine code, and is therefore OK. I like their approach to the mixing of COM with language features. I think they hit the right balance here, and like the idea of being able to call the libraries from any metro language, because at work I'm in a very mixed C++/C# environment, but too many of the people have "drunk the kool-aid" and are C#-only and are "ooo! scary!" about anything in C++. I like being able to still write libraries for them, and really, refining the API down can only be a good thing.
Ultimately I think the OS will do fine as long as they bring back the Start Menu. Still have the tablet interface, and I'd even use it as my "primary" launch spot for frequently-used things, but don't ditch the convenient repository that was the Start Menu. Especially without tutorials on how to customize it to MY liking. BIG need for tutorials. That's what's missing in this release.