The card has been absolutely amazing. The mana cost is negligible compared to Goyf, since your not running turn 1 Grim anyways, and wouldnt be with Goyf in this list either since it only runs 3 moxen, lotus, and in my case petal to help reach delirium. Turn 1 your dropping a dr. Shaman or wasting thier turn 1 land. Turn 2 your setting up your hand or a leovold, or Grim/Jace plus protection or backup. I would like to add EE or maybe some duress/thoughtseize, and may even try a singleton seal of primordium/pernicious deed, in there as additional backup turn 2 and for delirium. As far as his card selection ability it has been nuts crazy good. Think what dack does with Gush, he does it but up to 3 cards. Either binning lands to find business to Gush into, fueling delve for cruise dig or tasigur, or finding fodder for jace vryn, all has been great. I might even add back in yawg win. It being a 4/4 trampler is no small thing either. It has won me several games that bob, dack, preordain, or top, would have not due to its filtering ability and huge body. I really cant say enough about it. I highly suggest ppl try it out.