There are definitely far fewer apps in their app marketplace. However, the core apps that I use quite frequently are there and are just as good as their iOS counterparts (if not better...both Spotify and Twitter I prefer on Mango). There are a few exceptions here for me like 1Password which is not near as good as the iOS version but to be fair they offer it for free on Mango compared to the 15.00 price tag on iOS.

The one thing I'm really excited about though is that the developer tools are second to none. Microsoft has made it very simple to build very nice looking applications very quickly. As a developer that just moved to this platform I see the limited apps as great opportunity to help improve this platform even further and I plan on doing just that!