Went Grixis instead of Gruul to have some hand hate with duress and K command and the blue splash for iteration and tradewinds.  Tradewinds is great with Stone Rain dragon or Ruinblaster – you pick up one of their lands on their turn and return a stone rai creature to yours.  Gatekeeper\’s primary target is land so that while they\’re trying to rebuild their base they get pinged.