An ultrabook is built to run standard Windows apps with little or no modification, but app compatibility is less clear with tablets. ARM-based Windows RT tablets, for instance, will get their own version of Microsoft Office 2013 when they ship this fall. But the RT edition of Office reportedly will lack enterprise-friendly features such as third-party add-ins, macros, and Visual Basic for Application (VBA support). Microsoft is doing this to boost tablet battery life and reliability, The Verge reports. Of course, x86-based tablets will run full Windows apps and won't suffer this shortcoming. An interesting aside: Microsoft's move makes one wonder about the still-unannounced battery life of the Surface Pro and similar Windows 8 tablets.