It's not a big change if you don't want it to be. I've been using it on my desktop for a couple months now, and I can just ignore the metro stuff entirely. If you do that, it works exactly like Windows 7. I don't like the flat default window border theme, but tweaks are available to try to rectify that.

My biggest complaint is Microsoft's new music app. I'm a ***heavy*** Zune Pass user (I download thousands of Psytrance albums to find new music). The old Zune Software has a bunch of bugs (can't jump to a song by title in my collection, can't sort an artist's songs by name in the marketplace to avoid downloading duplicates, etc). I was hoping their new software would be better, but it's actually much more limited. It's also completely unusable on a desktop because the app doesn't have independent volume control (not even the Mixer in desktop mode will let you independently control the volume). So I've just been using the old software and living with the bugs.

I haven't used it on any tablets yet since I'm waiting for the Surface Pro (it's the only thing so far where the specs match my tablet criteria), so I can't vouch for any of its touch support.

Overall, for mouse and keyboard use, there's no major difference in Win7 and Win8 that's worth picking between the two. If you have a touchscreen though, Win8 should be superior.

After using it, it's not that bad. I honestly don't have any more problems with it than I have with 7 in general. I'm fine with the start screen. I can see why some people don't like it, but I only really have 15 icons on my desktop I ever use anyway; I used the start menu and taskbar more heavily, so others might have bigger issue with it. Personally I think the negatives are largely overblown. It's different, but I don't really mind.

I do think RT is hurt by having both desktop and modern interface. RT would have been a much more cohesive experience had it been entirely modern UI. That's my only major criticism that hasn't already been addressed by Microsoft in some fashion.

I've been using it for the last couple of weeks (in fact I drank all the Kool-Aid in one weekend and got a Windows Phone too...) and honestly I really like it BUT I will point out the first thing I did was install 'start8' from Stardock so that I had a start menu + boot to desktop. Beyond that however I find the OS to be faster and more responsive than Win7 (the boot time is INSANELY fast, faster than a fresh Win7 on the same hardware I find) and I've even come to prefer the visual style (I use Win7 at work on a comparable setup so plenty of compare and contrast time). For the upgrade price it really was a no brainer imo... that said, I do wish the 'enter' key would work in these forums in IE10 *sigh*

Silent deployment, new standards in GUI, extended DirectX API.
Another thing would be "Windows App Store".

For me it is good.

One thing that bothers me though is that the modern UI can only work on one screen at all times, so if I have the media player app docked to the left of my leftmost screen and open up the start menu or the side bar (or whatever they call it) on my rightmost screen, the app will suddenly switch screens, which gets really annoying after a while.

I've had severe issues with multiple screens and Windows 8, particularly when trying to view video on the secondary screen. Many applications just seem only to work on my primary monitor. Hopefully that's just an NVidia problem.

As for boot times, I guess I'm just fortunate to have had a great PC when I had Windows 7, that the upgrade to Windows 8 really wasn't anything noticeable for me. It boots up about 1 1/2 seconds faster than Windows 7.

Definitely get the start bar back if you get it. That being said, I'm honestly not too thrilled with the OS. The Metro interface is now cluttered with executables, even if they're the uninstall program that would never be shown on the desktop. And even things such as turning the computer off before you have the start button is not a 1 step affair. Yes, there are ways to alleviate both of the above issues, but a solid OS should not require intervening steps, but work right off the bat. This is an area where Apple does things right imho. All too often the UI gets put on the back burner, because management seems to think anyone can make one, but there's a difference between a UI and a good UI. And making a useful UI is an art.