Microsoft has a vested interest in pushing Windows Phone in enterprise, though according to a recent interview with Stella Chernyak, Senior Director of Product Marketing at Microsoft, they're opening up for mobile device management so other solutions can support Windows Phone 8.1 devices.
BlackBerry is very much in the same boat, having recently announced that in addition to supporting Android, iOS, and, later this year, Windows Phone, they're now allowing other parties to manage their devices. One of the early MDM partners of Microsoft's, AirWatch, is also working with BlackBerry. MobileIron is also on the list of beta partners supporting Windows Phone 8.1.
It's good to see Microsoft shifting to support the bring-your-own-device movement, which basically summarizes the entire state of phones in the workplace nowadays. IT guys need to be able to support a wide and dizzying array of phone types, and Windows Phone needs to be counted alongside them if it wants to get equal spread in the enterprise sphere. How many Windows Phones do you guys see in the workplace? Any of you IT admins that handle Windows Phone rollouts currently?