First off, the art is wicked awesome! Greg Staples knocks yet another one out of the park.
Now, to the actual card and it's potential applications:
Best Case Scenario:
You reveal
Emrakul. Then on your "free" turn, you swing for 21 flying?
Worst Case Scenario:
You sacrifice your 6+ lands and all your other resources, simply to reveal several lands (which you can't play) and some removal spells and such.
Overall, I don't think he's going to see serious play, but with an ability like that......it's hard to say. We also don't know the full RoE spoiler, which may have some additional cards that compliment our newest demon.
Spike Grade: 1 star (out of 5 stars)
Johnny Grade: 2 stars
Timmy Grade: 4 stars
Vorthos Grade: 3 stars