Not that bad
We got a few of those Asus VivoTab Smart in the office and they are actually not that bad. Admittedly I mostly used the classic desktop and VisualStudio. Though I'm sure some of the Modern UI apps are probably worth it. That Market application looked great anyway. You also need a few accessories to actually be able to use it properly. The stand/cover, a pen for when you are pissed off trying to use desktop apps with your fat fingers, a keyboard to actually do some productive work, a mate screen protector in case you get fed up looking at yourself in that glossy screen, and a sleeve (ISY).
Been travelling lately with one of those and a brand new ThinkPad Compact Bluetooth keyboard, that worked quite well for me. Good battery life, really small and light package so you can easily put it in your backpack.
Did not notice many people actually working with Android tabs and iPads on the move while I actually managed to be productive with that setup, though full HD would have been better obviously. You also very much need a small table to actually get it to stand, on your knees it won't work. Thankfully most planes and trains have that even in economy class, except maybe Heathrow Express but thankfully it is express.
The detached keyboard is actually quite good, makes me wonder if buying a laptop is worth it. I quite like working with the tablet on the table and the keyboard on my knees. Though I guess laptop would be the same just without the need for the table.
Anyway Surface Pro 2 and the likes look quite promising. It just does not make much sense to compare it with iPads and Android tabs.