I'm not just echoing what many others have said but this thing is really neither fish nor fowl. Its screen is too small to run the Windows Desktop and it doesn't have a physical keyboard available. And the Modern (Metro) interface, let's just say it makes me want for iOS.
It's not so much that the Metro interface is bad, it's just that it is different and not discernibly better than iOS or Android. The steps to close a Metro app are just bizarre. webOS had this right and iOS 7 pretty much copied that. Android isn't any better than Windows 8.1.
The Start icon appears in various places in the navigation and does different things depending on where you are.
Would you have figured out that this is the Desktop tile?
The physical Start button is capacitive so you have no sense of where it is nor does it "click" when you do touch it. There is some haptic feedback.
You can use the device without a Microsoft login but the Metro apps force you into using a Microsoft login. That means that you can't get e-mail (even Gmail) without logging into a Microsoft account first. Then that Microsoft account drags all its stuff along with it.
If your modus operandi is Microsoft that's probably good. If your modus operandi is Google or Yahoo that's at best confusing. I finally got the Mail app to read my Google e-mail using imap but it wouldn't send and didn't present any kind of error. There isn't a Google supported Gmail app and the Gmail app in the Store (Gmail Touch) wasn't intuitive to navigate, e.g. I couldn't figure out how to see my labels.
And the Live Tiles, they are pretty and "live" but some seem to change just to be changing. For example, the People tile keeps changing faces but when you tap on the tile it doesn't take you to the face that is presented. They don't represent senders of the e-mail in your inbasket. They're just random faces. Odd.
I really tried to like Windows 8.1.