In using tablets, like some others ultimately I've found that I only naturally use them to read books and documentation, or watch netflix - mainly because when I fall asleep using it I know I'm not going to roll over and break the hinge. This is still far from the most severe handling imaginable for any device and, as I'm not invested in selling tablets, I'm ok with this.
Even for my uses (and I've tried a couple others), they could leave the home - but usually don't. The reason being I only, and inevitably see tablets (whatever flavour) through a prism encompassing their limitations, evaluated against my already learned computer use and requirements - what's especially true and relevant to MS being the ARM Windows RT - through restriction _exclusively_* to the windows app store, meant at release throwing any incumbent UI or software advantage away, even for nerds - who are the most adaptable - but least likely to accept limited TIFKAM analogs. And as all such apps had to be new they're inevitably limited. No matter how good the developer, version 1 always sucks.
That was never an amazing sales pitch to any part of the market, just an opportunity to gain some leverage simply wasted, in the search for the golden goose of (of course) a 30% App store cut on every software purchase.
It certainly won't apply to everyone (some are in fact perfectly fine with typing on a BT keyboard within a crappy, laggy cloud app - if you're happy, I'm happy for you) but to me, the persistent irritation that I can't run putty, chrome, firefox, - pidgin, cygwin, irssi - or basically (to within a rounding error) - any program ever - and thus to not actually be able to use it like a small laptop is the ultimate problem, and to some extent it applies to each platform, no matter how determined you are - at least without cheating with rdesktop, which sure, might be a fine use-case for specific scenarios, but probably not one involving "being outside" or for that matter, "upgrades".
The Surface Pro (x86) of course /can/ be used a small laptop, but (crucially) not at the tablet price point. I've had, and sold a Surface and if actually undecided, I still find the form factor dubious. I'd rather have an ultrabook - which with the same 4th gen haswell cores has as long (longer, if we're counting) a battery life as the Surface Pro 3. So that's what I have.
In mobile terms - I settled on use of phablet (on which I could netflix, or read books as well, if I were to want to that badly, while not wanting to kill myself when using the onscreen keyboard) - as the best compromise in that it has the advantage of being both mobile, and not needing /another/ pocket or separate bag - because a tablet won't support full-fat computing and a laptop at least might. So if I want to do any real work I probably still have to take the laptop no matter what. And if I do that, then taking a tablet as well is kind of redundant.
The greatest missed opportunity so far - noone made a serious tablet UI in the LCARS style. The future will not be forgiven until this is changed.
* in fact 8.0 release of WinRT was jailbroken - numbers of windows 8 ARM apps were compiled for it, even a x86 translator. I didn't keep up but 8.1 jailbreak took a "while" or never - disappointing. If it wouldn't have made RT a success, it'd have had a niche.