I would go with electric brakes , much easier to install , usually just changing/adding backing plates & drums and run some wires and a back up battery . Most trucks are already wired to accept a brake controller .
Surge brakes have that funny feel, that I never cared for, like getting hit in the rear when you are stopping. also there was some confusion about how legal surge brakes were this site should clear that up.
Centreville Trailers Surge Brakes New Federal Ruling