A couple of decent editorials from a developer of Marble Blast Ultra for XBL Arcade. He talks about it in more of a general 'indie developer' context rather then "XBLA FTW!". I thought it was kind of interesting and spells out more clearly things we kinda knew all along.
Part I:
http://makeitbigingames.com/blog/?p=7
Part II:
http://makeitbigingames.com/blog/?p=13
Part I:
http://makeitbigingames.com/blog/?p=7
Part II:
http://makeitbigingames.com/blog/?p=13