I can be at the office editing a document on my keyboard/mouse laptop, save it to skydrive, and it's already there on my 8" for review later. Quick edits on the go are a breeze, since I have the identical MS Office software running in both machines.
I can review documentation in a git repository by actually installing git for Windows and cloning the repository. Now I'm not saying I'm going to actually code on an 8" Atom device, far from it. But the fact that I can participate, using the exact same tooling in the exact same manner, as is fitting for the device, is brilliant.
The only difference is I use 90% Metro Apps on the 8", and 90% desktop apps on the laptop. It's the plumbing that's one size fits all, and once in a while you cross the boundaries of the UI and it works well enough. You're not giving anything up. You have it all.
One size fits all is great, I'm a fan.
My mother on the other hand is quite adept, and dislikes it. Well, she did, until 8.1, and I configured it to use the desktop as the main interface, and she got used to it. Now she likes it too.
Personally, I haven't used Windows in half a decade, so it's interesting to watch the reactions too it. I think they are moving in the right direction, but need to adjust the desktop story a little.
That's my personal experience. If you want to call me a shill, then say it, rather than insinuate it.
Edit: Apologies, that was antagonistic. I was a professional salesperson for 7 years - I sometimes lapse into sales talk when discussing any product. Usually it's things other than Microsoft, and I'm not joking when I say that the last version I used was Vista, but I honestly think 8 is interesting, if unpolished. My family isn't adept other than my mother (she's 41).
As a long time user of Windows, I'm frustrated, but maybe they're going after new people and they don't have the same expectations as me.
Swiping is awesomely natural on a touchscreen, but obviously sub-optimal otherwise. Reliance on a swipe gesture should be avoided in UI design for a mouse/touchpad and keyboard environment, in favor of buttons and menus, and mouse wheel/two-fingered scroll support.
Also, the several seconds I've spent trying to open stupid like charms menus and things meant to be swiped with a thumb were not an enjoyable several seconds.
Why must we try to make them the same? I would argue a set of well defined junction points like Apple did with airplay in order to share content between mobile and desktop segments is a way more elegant solution.