Unfortunately I don't think any of those sites really come close to the App store. The App store is simply a new phenomenon that is unlikely to be matched by any Windows Mobile site. I don't own an iphone and I don't plan on getting one... but that is just a reality.
Just on a personal note, just last night I briefly exchanged phones with a friend with an iphone. It was one of those friendly comparisons and test drives.
He marveled at my ability to tether and use my phone as wireless router. He also thought it was cool how I could tweak so many different aspects of the OS.
I marveled at the sheer number of Apps he had on his phone. He said that was the best thing about the iphone. He said that literally hundreds of new Apps come out each week with most Free or costing only $.99. An man, the games that he has! I just hope a few get ported over.
Interesting article on the App store:
http://www.newsweek.com/id/174266