HibameThis drop is for a 2 pack for the price of one. Not to mention that I believe that $40 is the minimum on their site to qualify for free shipping. You get free shipping here and a second pair. The two aren't really comparable - Massdrop wins without a doubt.
hearfOn the sunhaters site the Deric and Leonard styles are $15 each, however the polarized styles are $40 a piece as compared to $31 each here on Massdrop. So I suppose either way you are saving the shipping cost but it seems if you don't get a polarized style then that is all you are saving.