Integration with AD makes WinPho a pretty easy choice for cheap business BB replacements .
The lack of apps on WinPho doesn't really matter when all you really need are calendars and email.
The built in off-line Nokia Maps can be pretty big plus for those that have to delve into remote areas lacking in a mobile signal.
MS inability to keep up with the Facebook API might put of some folks outside of business.
Not sure how WinPho 10 will do. Windows 8.1 for phones works really quite well. 8.1 just sucked on everything else.