SRAM has been been on an innovating spree lately from their 1x12 speed Mountain Eagle Group to their 1x Road and CX Groups. Now with Red's new wireless electronic shifting eTap they can compete with Shimano Di2.
I am a little late to the game posting on SRAM eTap but thought now was a good time with Shimano's recent upgrade of their 10 Edition Dura Ace R9100.
I believe The electronic shifting would have mass appeal, but whether the price point will ever come to a place where the common rider can try it is another question. I've never considered the Shimano Di2 personally, as I don't have a bike setup for the interface. But with SRAM Red eTap, I could install it on an existing frame with no integration issues; which is especially appealing as someone who likes to ride vintage frames matched with modern components.