Can't answer to any sales, but I like the discussion about the different decks.
Koth's deck is pretty good once it gets up and running. It scales up well as the fight goes on, and the Rockslide Elemental can become pretty huge.
I used Jace's deck to beat most of the Revenge decks on Planeswalker though... Don't know if that means the Jace deck is good, or just good against most decks in game. I find it hard to believe it's really any good when all the phantasmal creatures go poof when targeted with anything.
I thought overall though most of the decks were a disappointment, given how fun some of the ones were from the first game.
And as a side observation, for a game called Duels of the Planeswalkers, you'd think they have, ya know, some Planeswalkers.
Still, worth it just for the free Grave Titan foil.