There is no "best for all situations" toad brake. That is why some companies like Roadmaster make several kinds.
"Best" depends on factors such as:
Is coach gas or diesel?
How often do you change tow vehicles?
How much of a hassle do you find moving/storing a "brake in a box" vs permanently installed systems?
The more you tell us about your needs and equipment, the less "here it what I chose to best fit MY, repeat MY needs" and more about the best options for you.
Example: the fact that the Roadmaster Invisibrake was the best solution for MY needs (and it was) does not mean it is necessarily the best for YOUR needs.