I hated Windows 8 before I actually installed it.
The fears of "new thing" I had were eliminating the Start Menu and that Metro would be compulsory. It turns out it's all exactly what I've wanted in computers.
I've had Mac friends bitch at me, like "I can tell you're a Windows user!" because I maximize everything. Since Windows 3.1 the only state I've felt comfortable with is maximized with a taskbar. The only time I want to see more than one window is when I'm dragging something from one to another.
People say this is a matter of multitasking, but multitasking doesn't exist in any real way until there's independent processors. Computers don't "multitask", they shuffle short parts of a job together to give the appearance of multitasking. People are the same, and I'm just not built for it. I only want to see what I'm working on and something telling me when it's time to look at something else. I benefit highly from a non-overlapping user interface, which is what Metro offers.
Ubuntu's early netbook designs were very inspiring. A few applications worked together to clean things up, Maximus would maximize everything and take off the window frame and buttons. Window-picker-applet would replace the regular tasks applet in Gnome, cleanly fitting in with the frameless windows and offering a fixed close button at the end. What they had effectively done was turned the taskbar into browser tabs and I was thrilled.
The Start Page is an excellent replacement to the Start Menu; When I opened the Start Menu, I wanted to look at the Start Menu, and I just happened to have to kludge through a million things or pin a short list of things to the top of it that depended on my resolution. With the Start Page, you pin everything you want and ignore the rest until you need it. I will never have to think to myself again, "Well, I don't want this application on the Taskbar, but to put it in the Start Menu I'll have to remove something else..."
As far as the Windows Store goes, it's just another case where IE got the spotlight. You can use alternatives, the ethical question is whether Microsoft will let you choose them (they will) and if they're play dirty to hurt the competition (they probably won't, much, nothing that they won't be condemned for). I'm looking forward to Steam's Metro app, Chrome's Metro app is already fine.
Really, it's entirely possible to create a wrapper that will put any application into a maximized frame to pretend to be a Metro-native application. I just wish Metro didn't segregate from the Desktop so much and that it had a cleaner way to switch between Metro and Desktop applications.
Finally... I don't know what people mean about this nonsense with "only good if you don't use a keyboard or mouse". When you're like me and you always maximize everything, there's no damned difference. If you don't, don't use Metro because the rest of the Windows 8 is a hell of an improvement.