Lawrence,
Everyone that I know who has an Air Force One braking system likes it. However, the installation can be a little involved on some tow cars, making for an expensive system.
I have been using an M&G tow brake from M&G Engineering for 15 years on two different Jeep Grand Cherokees, and I could not be more pleased with the system. The only problem with the M&G system is that there is not enough room on some cars for to install the cylinder between the master cylinder and the brake booster. However, if your tow car has the room, it is a very good option for a tow brake.
Gerald