You don't actually get miles, you get points in their program which you can redeem for flights. This effectively results in double-dipping, as you still get your standard FF miles in addition to the 1 point per 3 miles (and the 1 point per dollar). The unlimited companion tickets look nice if you do a lot of domestic flying. They claim the points can be redeemed on any airline, and have no maximum ticket value, so if they actually pull through, it looks pretty darn good.