If you want or need to use Microsoft Office and services, you'll want to use them on iPhone.
We've already covered how iPhone and iOS provide not only a great Apple app experience, but a great Google and Microsoft app experience as well. Because of the iPhone's popularity and uniformity of platform, it's not only easy to develop for iOS, it's hard not to. That may be why a lot of people who prefer Google or Microsoft services also prefer switching to iPhone to use them on Apple's hardware. It's not just Apple enthusiasts who say so either.