We use Brake Buddy. At the time we bought it we had two vehicles set up as toads so it was nice to have a portable brake. Our coach bears a label by the hitch reminding the owner that the chassis brakes are rated at GVWR --NOT-- GCWR so towed vehicle brakes are required.
There are all manner of discussions based on Necessity, Safety, Legality, even Morality. Although I have not heard of RVers being screened strictly for toad brakes (except in British Columbia!), I get a lot of peace of mind with supplemental braking including breakaway capability. I towed our Frontier without the BB a couple times and wished I had it. With the BB, and the big late model front brakes that came with my front axle upgrade, the rig stops very well. Probably not car-like, but way better than I'd expect our combined 18,000-lbs to do.
