Earth Splinter has been one of my favorites. I start level up that Splinter (as @SumatraNate) before realizing all of the pieces and components of the game.
I have stuck with it and Maxed out a few cards. At the end of the day, I would prefer to see earth pop up over any other splinter for my daily rewards.
I think it is good to play at lower levels again even after playing at high levels. It could come in handy when competing in tournaments.
RE: Earth Splinter My Boot!