Been using it for almost a year now. I have a lot to say on this because I've been a "Metro" developer for over 2 years now and I am trying to figure out Microsoft's strategy. First off, I want to state that if you have a windows phone (who does besides me right) you understand how Windows 8 works already, and how metro operates.
I wanted to address a couple of issues.
1) No Start Menu. This had to happen. I know there a lot of vocal people on the internet who see the loss of this thing as a huge issue. The facts are, no one uses it anymore. You search for stuff. A very large majority of people do not click through the start menu these days. They click start, and search. In windows 8, you just type. No clicks. You want to open calculator, you type "C" and all apps starting with C appear.
2) Metro. Metro is a huge change for a lot of people. You are being forced to use a UI Design that you may not like. This was done for the single reason to unify all devices. XBox, Phone, PC, Tablet or Laptop. The reason for all this is that you can have all these devices, and they all look the same, you interact the same, it is one world. You hate the fact this is forced on you, but the times they are a changing. Even though YOU don't have a tablet, the rest of the world will soon. Exmaple: Many large 10K+ sized, are buying tablets for employees this year for all employees. So mobile is the future even if you don't want it on your PC.
3)Desktop VS Metro. There is still a Windows 7 Like desktop. It has no start menu, you will be able to run all your old apps there. These will be different from "Metro" apps. MS is trying to create an ecosystem like iOS where there is a managed market, tested and confirmed apps/games. To do this, they needed to force app devs to use a common UI scheme and language. This is Metro.
4) I hate it, it's confusing and ugly. So, you may not like the way metro looks, that's fine. Aesthetics will never please everyone. That said, MS did a large amount of studies to see how people use computers, how people use windows and how people interact with technology when they made decisions in this. Eye tracking, heat maps etc. It takes getting used to, but the hot spots and gestures etc, are very helpful in launching things and getting to settings faster.
It's a change, yes, and it's jarring, yes. But the changes are for the better and only help you navigate your computer.