Apple and Google are dominating the smartphone OS market and I don't see how two slow-moving companies will make a serious dent in the consumer market. How many people wold would give up their iPhone for a Windows phone, especially as an early adopter? I'd be very surprised if any Windows Phone gains serious traction with consumers.
The best shot I see for Windows Phone success would be in the enterprise market where easy/free compatibility with MS Office products and other MS products used at work could be a large benefit. But Apple is making headway here as well so it could all be for naught.