Windows Phone 8 is the only reliable enterprise smartphone OS in the USA right now
iOS 6.1 is crashing thousands of Exchange servers around the country right now due to the calendar bug -- many enterprises are having to ban iPhones with the update from their servers as a result, tossing hundreds or thousands of users per site off the server entirely. Plus, the update also leads to 3G connection failures. Carriers and IT departments are scrambling to urge users NOT to upgrade or install 6.1 due to all of its serious problems, and I'd imagine that some procurement people responsible for replacing BlackBerry handsets with iPhone 5s and iOS 6.1 are sweating over job security right now.
And Android is now projected by Trend Micro to have over 1 million malware apps by the end of 2013, meaning that Android BYOD users will be exposing corporate passwords, usernames, files, servers and storage volumes to compromise, access, espionage and even malware infection vectors via hundreds of thousands of Google Play malware apps.
BlackBerry 10 appears secure, but isn't available in the USA for at least a month and a half.
Microsoft should probably advertise that WP8 is the only secure, stable and enterprise-grade mobile OS on the market right now, for both BYOD and corporate installations.