I don't know why there complaints about the marketplace. The WP7 platform has been a huge hit with developers; just take a look at what's out on the marketplace: http://www.windowsphone.com/en-US/apps. From everything I know the review process is leagues better than the Apple's in that you get actual feedback about the issues whether or not your app is acceptable. Microsoft has put out a podcast from Redmond that covers what is going on with the platform to help developers http://wpradio.podcast.windowsphone7.com/rss.

Then there is the fact that they make it free for students to develop with dreamspark accounts. https://www.dreamspark.com/Products/Product.aspx?ProductId=2...