I have a Windows tablet, the Linx 1010 not the Surface, but the OS is exactly the same and it's great. The build quality of the Surface is excellent, as it's similar to my old Surface RT and fixes the problem with the RT, that it only runs apps and the app store is limited.
It's great having the exact same OS on a tablet and my main PC, makes it far easier to share programs and files, and using the same Metro apps on my desktop PC is very useful. I keep the Twitter app open on my PC all the time and it's far neater than having a Chrome window or tab open for Twitter, and it's easy to quickly swap between Twitter accounts ( I have a personal and a work Twitter ) and to have the exact same app on the tablet.
It's also great on a tablet having the very same control of files and settings as your PC, since you can choose to simply mirror your PC settings with your MS account or have different settings on the tablet but you haven't got to learn a whole different OS. File management is far better than my Android phone for example since you have a choice between the finger-friendly tablet UI app for pictures etc or you can open the traditional windows file explorer if you want to do some serious housekeeping or moving files around.
With Windows 10 you can choose between a tablet UI that is easy to use with fingers or a desktop UI that is better for use with the keyboard and mouse. Personally I never use the tablet UI as I find the desktop UI is perfectly fine to use with fingers and I prefer it.
In tablet mode apps snap to full screen or you can snap it to half screen and run a different app at the same time. You can slide the bar to make each app bigger or smaller, and it doesn't blur the screen when it's doing it like the iPad does. In desktop mode windows are exactly the same as your PC, you can have as many as you want and any size or shape you want.
Full programs like Chrome can be used and have some of the same tablet friendly controls, like being able to swipe a page right to go back a page for example, far easier than having to press the tiny back button on the iPad.
You can plug a lead into your HDTV or a second monitor and extend the display, ie have different things on each screen. You can use it as a dual monitor PC or you can play a movie on the TV while surfing the net on the tablet display.
If you have kids you can set up separate user accounts so they can play without being able to read your emails or look at your photos. It comes with a years subscription to Office 365 or you can just use the Office Mobile apps which are free but don't have the full functionality. Or of course if you already own a full licence to Office on your PC you can just install that. Plus with USB ports and a micro SD card slot you can easily add external hard drives or extra storage, a decent 128GB micro SD card can cost under £40.