I think business usage on a tablet is governed by the following factors:
1) network access(wifi,3g/4g , tethering)
2)apps for business, not limited to legacy apps.
3)text entry
4) expansion support: mice,keyboard,pen drives
5) encyption and company policy
In my view it also depends to the particular app you are using and how much a person is comfortable using the virtual keyboard.
Apps like numbers are almost unusable on the iphone but great on the ipad air. The quickoffice spreadsheet on my nexus 7 is not a app that i am crazy about. It is slow, confusing and often counter intuitive.
Coming to text entry..
I dont like solutions like logitech ultrathin becuase it means raising my hand from the keyboard to use the screen. But i like the fact that the whole screen real estate is available to use.i would love something with integrated touchpad and something. Big. And comfortable..
I have suffered a lot in the past 4 months with my windows 8 laptop. I cannot bear to see it on any other of my devices.
Windows 8 tabs do win on all 4 categories i listed , but for me i might as well open my windows notebook and wait while it searches for the wireless signal.