I have a Class A motorhome and have a brake controller (SMI Silent Partner) on the Honda Odyssey we tow.
I installed the brake controller first and foremost because I just thought it made good sense.
As many of the posts attest, interpretation of the various state laws seems to be imprecise at best. However, I DO KNOW that in my owner's manual, Workhorse has a statement that anything towed over 2,000 lbs. (might be 1,500...I'm going from memory here) requires a brake controller.
What that says to me is that should I be involved in an accident, and some lawyer reads that statement, what defense do I have if I don't have a brake controller installed? I wasn't really worried about the state laws etc., but I don't think it would take much of a lawyer to convince a judge or jury that I should have a brake controller when towing a 4,500 lb. vehicle.
The side benefit is I believe I'm also covered by the state statutes, whatever they may be. Although I really am not worried about being pulled over for that.
But mostly, I have peace of mind. I have had one situation where I crested a hill and the traffic was at a standstill. I jumped on the brakes HARD. I was able to stay in my lane and missed the vehicle in front of my by about 10 ft. If the Odyssey wasn't applying it's own brakes, I believe there would've been a collision, or I would've had to drive off the road.
As I said, they supply peace of mind.
~Rick
2005 Georgie Boy Cruise Master 3625 DS on a Workhorse W-22
Rick, Gail, 1 girl (27-Angel since 2008), 1 girl (22), 2 boys (23 & 20).
2001 Honda Odyssey, Demco Aluminator tow bar & tow plate, SMI Silent Partner brake controller.