I wanted to update my assessment of ChessKid. I believe they changed the site so that you can no longer abandon a game in play because you are losing without penalty. This has vastly improved the experience, although it is still rare to play to checkmate (other play usually resigns--ok often, not all the time). Also, the bugginess we were experiencing seems to be limited to the mobile version, which is still not good, at least on my Driod.

We have actually upgraded to a Gold membership so DS can watch all the videos (I am a chess idiot, but they seem very good) and get all the other benefits, including unlimited puzzles and practicing positions aginst the computer. DS REALLY likes the site and has improved a lot since using it consistently.