I have recently installed the MaxBrake controller in my TV and am, so far, pleased. It is the only aftermarket controller on the market today that senses the brake fluid pressure in the TV's braking system, and as a result, it is more responsive and doesn't have the quirks of the accelerometer-based devices that can only guess at how much braking the driver has applied.
I'll post a fuller review with photos later. It does have some minor things I would have liked to see them do differently, but there's really no other controller worth considering at this point unless you're trying to save a buck.
Stories like these
make me willing to spend a few hundred bucks to have better brakes. If I'd been the one who hit the kid, I'd remember it the rest of my life and wonder what I could have done differently.