If you didn't know already, all Windows RT tablets will have Office 2013 RT, but now rumors are surfacing that even if you have the full product, you might not get all the features of the x86 version of Office.
Word (ha ha, no pun intended) on the street is, that in order optimize performance and battery life, Microsoft pulled a number of features from the ARM-friendly version of its productivity suite.
Among the missing features is support for macros, third-party add-ins and VBA scripts. A small number of other features are also reportedly on the chopping block, but with no final product yet, we will have to wait to see what actually gets axed in the final version.
Source: The Verge