Be careful with the "It can do a lot more than the iPad can" line. That has been said about Android for forever and I couldn't find anything my N7 could do that my iPad couldn't.
It might be able to do things in a more recognizable way (especially if you're a PC) but the iPad (with 600,000 apps - almost half of which are specifically written for the iPad) can do a lot of things people either don't realize or ignore because it requires a different program.
Kinda like saying "The iPad can't run MS Word" and taking that to me it doesn't do word processing/document creation. Well no, it can't run MS Word but it can run Pages, which in my experience is just as effective.
I understand, many people have certain programs they use and legitimately cannot switch from - but that doesn't mean the iPad doesn't have the capacity to do that task. There are also many tasks that are a preference to the user - and would therefore be a main reason to choose one platform over the other. But claiming the iPad is inferior based on your desire to mess around in the file system (when the way Apple runs file management behind the scenes is preferable to many people) shouldn't be an overall indictment on the iPad - simply that you prefer to be able to open the file system.
For which case you should buy a Surface
----------
Overall - the consensus from a lot of articles I read and from my buddies who work at BBY (based on their interactions with customers) is that Win8 isn't a huge success - rather too different from the standard windows and people are cautious of it.
I think on a large-scale Win8 will see a pretty slow adoption rate - but that's just my opinion based on my own research and readings.