Think the sway-away's are the way to go - if you plan to offroad this vehicle. If the goal is to keep this a street queen, I'd stick with the Rad-Flo's. I don't see the point of spending the extra coin for the Sway Aways, unless you are looking to convert to 4x4 and enter the slippery slope of the mod bug disease.
As far as teh Rad-Flo's vs. the Bilsteins in the rear, I can only say that there a couple of people on this board that swear by the Bilsteins and run them wherever they can. I'll probably be putting a set on the Super Duty at somepoint.