Check the full post for a Microsoft iOS app list; also see Microsoft delivers iOS, Android versions of Delve (ZDNet) and Microsoft acquires mobile business intelligence leader Datazen (The Official Microsoft Blog)
"Just a few years ago, there was a sharp divide between fans of Microsoft and fans of the iPhone. But in this “mobile first, cloud first” world, it’s now possible to combine Apple’s iPhone hardware with Microsoft’s best-in-breed productivity apps and not feel terrible about yourself. Things really have changed, and for the better.Microsoft + iPhone - Thurrott.com
And if you are a Microsoft guy, there are good reasons to choose iPhone over Android … and even over Windows Phone. Microsoft mobile apps generally appear on iPhone before they do so elsewhere, and certain Microsoft mobile apps are only available on iPhone, at least for now. In several cases, you will see finished Microsoft apps appear on iPhone, whereas Android receives a rougher preview release instead. In many ways, iPhone—or iOS more generally—is the place to be if you’re interested in Microsoft’s mobile solutions."