tl;dr Win8 is a great OS but with some stunningly bad UI mistakes that with some effort can be fixed.
I just installed Windows 8 and have used it for a couple days.
First the good.
It is fast and stable. It is my #1 OS of choice at the moment - BUT ONLY IF you first take the time to fix all of the horrible UI design problems.
It comes pre-installed with a great anti-virus program.
The task manager is nicely improved.
They included the ribbon from Office in file explorer. I don't like this but I think it is probably just because I'm an old fuddy dud. If you are used to the ribbon then it might be a nice new feature but it slows me down.
Lots of little things like improved defrag, disk checking, memory optimizing, aesthetically pleasing flat design style.
The flat UI design is a huge improvement over the default Vista/7 Aero glass design BUT they removed nearly all options to tweak it in Win8.
And the bad.
Oh my freaking god what the hell were they thinking. The user interface is absolutely horrendous.
The entire UI department needs to be fired. Or it seems they just hired a bunch of 3rd graders so "flunked" is more appropriate than "fired".
It is a desktop operating system entirely designed around touch. Even if you are one of the 1% that has an option of a touch screen monitor on your desk or one of the maybe 5% using touch on a laptop you still want the option to use a mouse most of the time.
Adding their new touch interface "metro" in addition to the start button might not have been the worst idea but completely deleting the start button with no option to re-enable it is insane. Balmer said removing the Start Button was "betting the company". If that is true I'd love to play poker with him because he has no idea when his hand is crap.
The start button is hugely functional and the entire target audience is comfortable and familiar with it and it has almost zero resource drain. There is no negative to including it.
Why did MS do this? Because iPhone and Android are kicking MS butt in the new smart phone market. To compete in phones MS needed to pull weight from their desktop monopoly. They tried to have a similar interface on both phones and desktops. Developers would then make apps for the MS phone because they would also have instant access to the huge desktop user base. And users would feel comfortable using a MS phone because it was just like their desktop. The huge problem is, you use a desktop and a phone for different reasons and having the same user interface on both is fail.
So much fail that MS admitted their mistake and said they would offer a free upgrade to fix the problem. That upgrade hasn't been released yet. Hopefully it will fix all of these problems and make Win8 a beautiful OS. I have no idea why it is taking them so long to release it.
The switch from the start menu to metro is by far the biggest problem with Win8 and that may not seem like much is wrong but they try to incorporate metro with the entire OS. By default nearly every file opens in metro. It is one of the hugest user interface design flaws I have ever seen.
One other huge and obvious flaw, the scroll bar is light gray on white. Almost white on white and nearly impossible to see. That wouldn't be so bad but they also for the first time since 1995 removed the option to customize the colors of UI elements. I can not imagine how screwed up their quality control department must be to allow such a fundamental and easy to spot problem make it to production.
I don't plan on using any metro apps but they obviously want apps to be the main way you use your desktop. Metro Apps run fullscreen - no option to put them in a window. The OS is called "Windows" and they are trying to remove the option to run programs in windows. Why! How did product testers not stop this.
My biggest complaint of Apple has always been that they don't respect power users. They treat their users like they are grandmothers. It now looks like MS is moving in this direction. They removed many customization options that have been part of Windows since 1995. The only reason to remove them is they don't respect the typical user's intelligence.
How to fix these problems.
MS didn't make it easy to fix these problems but with 3rd party software it is possible.
There are a couple different options to add the start button. I went with Windows 8 start menu returns with Start8 from Stardock!
But you can also use anything from here
List of Start Menu replacements for Windows 8 - Wikipedia, the free encyclopedia
List_of_Start_Menu_replacements_for_Windows_8
For more information and alternatives.
How to banish Metro from your Windows 8 PC forever | PCWorld
For the scroll bar I only found two solutions.
1. Get a wheel mouse and accept that you will never have a visual que for the page position.
2. Install Skin the Windows desktop interface with WindowBlinds
3. Use another OS.
I wasn't really happy with any of those options but I went with number 2 which does fix the problem.