Let me explain why Windows 8 tablets simply don't work well, at least not in their current form, and how to minimize the pain if you're forced to use one. Do keep in mind that both Windows 8 and Office 2013 are still in beta, so Microsoft could still fix their flaws. However, time is running out for Windows 8, which is expected to be sent to manufacturers in a few weeks for products to ship in October. Office 2013 is slated for early 2013, so refinements may still be possible.
Let me be clear: The problem is mainly Windows 8, not Office 2013 -- which is a crying shame because Office 2013 so far will be available only for Windows 7 and 8. Its only mobile outlet is the one you likely won't want.
A tablet UI that's hard to touchIf you don't have the latest touch tablets -- those specifically designed for Windows 8 -- don't bother getting Windows 8. It has trouble with on-disk BitLocker encryption with devices that don't have a Trusted Platform Module (TPM), a rare feature. Even worse, the work-around to enable encryption on a non-TPM device is painful. Many such devices don't have native Windows 8 drivers, so you can't use an onscreen or physical keyboard at startup, such as to enter safe mode or input your BitLocker password for the initial encryption.
I had that problem with a Samsung Slate from mid-2011, meaning I could not access corporate email from it. Windows 8 may run on older computers, but when it comes to tablets, Windows 8 really needs new devices designed specifically for it. The good news is that few people have bought Windows tablets, so most people won't have legacy tablets that pose questions about compatibility.
Let's assume you have no legacy Windows tablets to worry about. You still have to deal with what my colleague J. Peter Bruzzese called Windows 8's Frankenstein user interface. An Intel-based tablet runs both the Metro interface, which Microsoft now calls Windows RT, and the traditional Windows 7 interface, which it calls the Desktop. The two environments interact poorly and require you to change mental gears each time you switch among them. (ARM tablets will run only Windows RT, which will include a full version of Office, Microsoft promises.)