iPhone vs. Android for someone otherwise in Microsoft ecosystem

I'm completely in the Microsoft ecosystem. I have a Win8 PC, a Surface, an XBox, and a Windows Phone. I also store all my documents and pictures on Skydrive, and use Outlook.com to manage my email and contacts.

Unfortunately, I may have to switch away from Windows Phone -- there's a mission critical app I need for work that's just not available on Windows Phone. I was wondering what the 2nd best alternative (Android or iPhone) in people's minds were for someone completely in the Microsoft ecosystem. At the very least, it needs to offer excellent contact/calendar/email syncing with Outlook.com/hotmail, Skydrive access, and basic OneNote. Everything else will be the cherry on top.

(Please don't tell me to just stay with WP - that's not helpful advice; if I can find a way to do that, I will.)