I don't understand why you are even considering buying a WP Nokia. That is not Nokia anymore - it is ruled by Microsoft. And asking why not to buy Windows Phone? Well, why do you think no one buys it? It is ages behind MeeGo and even if it wasn't, it is a closed, proprietary system. No other big company is as bad in caring about customers as Microsoft...
Have you seen the great projects on this forum? You can forget about all of this on such a closed system. Honestly, I don't understand one single second considering it.