While it may not be the cream of the crop, I`ve had good luck with a Reese Heavy duty digital. You can set the power level for different trailers and the gain seperately. I`ve used it for my 5th wheel weighing in around 8500 and my 30 ft gooseneck hauling up to 20K and it has been flawless.
I use one of these as well. I just connected it to the factory trailer brake adapter that came with my truck and I am on year number 4 with it - no problems yet.
In the case of these things, I think the less electronics the better but that's just me.