Damon:
If you really want the best, then you need something that will actually know what you want for braking effort. The Jordan does this with a link, and that was fine when that was all that was available.
Rusty's comment on hydraulic-controlled controllers was appropriate until very recently. The old versions of this used a brake line from the master to a hydraulic cylinder in the controller, using a fair bit of brake fluid and displacement. There was a lot of worry on weather on not the extra displacement would bother brake pressure differential switches (sometimes it would) and later ABS systems, or more to the point, liability on the corporate insurance policy for cutting into the brake system in the field.
Finally, someone has the brains and the bawls to use modern electronics to measure the brake pressure at the master cylinder and feed it digitally to a controller. This is the new "Brakesmart" controller from Master Brake Systems (
www.masterbrake.com). It can be adjusted to give ANY amount of trailer brake in a variable proportion to the tow vehicle's actual brake application pressure. When used with electric brakes, it will identify the number of axles on the trailer, display its choice, and put out the amperage needed for that much brake. It can also be boosted to double voltage for very heavy trailers with electric brakes.
It was desinged to go with their electric over hydraulic, and now air over hydraulic brake systems. It will control them, air suspension and air jacks, as well as take air suspension pressure information from the trailer and compensate for load by varying the brake pressure in their actuators. Of course, if you really want the full meal deal, you would want to go with disc brakes and a Master actuator, which can then be upgraded to full ABS!
None of this stuff is cheap, but if you are at all serious about safety, it will be the best dollars you have ever spent. I have had the Brakesmart unit for a few months (including one solid month in the Rockies), and it has been impressive so far (reserved final opinion until an actuator fault has been cleared).
Pat