While the Eldrazi's "cast" line helps against countermagic, it hurts elsewhere, by not working well with effects that put the creature into play (reanimation, Defense of the Heart) or blinking effects
Its a staxy card thats easy to play around, but slows opponents down significantly
You don't however need to go down the tribal route, any sort of token or weenie deck with any sort of sac outlet will empower Sharpshooter plenty
Upon entering the battlefield, Gisa and Geralf put the top four cards of your library into your graveyard
I played against a huge swath of aggressive decks and repeatedly trounced them
Like any new Magic set, cards are already available to pre-order, with varying prices and availability