http://www.engadget.com/2010/10/11/xbox-live-for-windows-phone-7-your-xbox-isnt-in-your-phone-yet/ said:
The good news? Games look and play great, just like you might expect from an iPhone or Android level capacitive touchscreen platform, with The Harvest as an obvious and very important standout in complexity and polish. The bad news? Everything takes forever to load (our rough estimate is about three minutes to start playing in The Harvest), and when you don't have any multitasking, that's a really bad thing.