I use the Prodigy and it's great, a big upgrade from the old Draw-Tite. Best way to think of the proportional controllers is that they use the gyro-chip, which is the same chip that made the Wii possible and that let's the iPhone have apps like a level, etc. The chip in the controller actually senses how fast the truck is decelerating and increases current to the trailer brakes proportionately. Result is very smooth and safe braking.
Regarding the hitch, sounds like some guys know the Blue Ox and like it so probably a good bet. As I said the hitch hardware is not as important as how its set up, so pay attention to that and re-adjust after you pack the trailer.
Good luck with the new trailer and be sure to post some pics over in the TT forum when you pick it up!