As a user of XNA and XNA GSE since Beta 1, all I can say is that it totally kicks buttay. If my hunch about what rodawgg will show in the second video, some of you might be amazed at just how powerful and capable XNA is.
There's already a pretty strong community behind it to. Just keep your eyes open as I'm sure it will really start to blossom as time passes. I'm hoping that the coming of XNA will lead to some _very_ interesting experiments in game play mechanics and game types, just like some of the innovation we saw come out of the first Shareware push in the 80s.
Plus, come on, you can see your own code run on the 360! Writing your own 360 games using XNA, how cool is that?