I have the Prodigy and have nothing but praise for it!
I tow daily delivering equipment with trailer weights running from (empty) 2000 lbs to 12,000 loaded. This is when the "Boost" feature is nice, lite load=no boost: 12,000=boost.
The "boost” feature just starts initial power to the brakes higher.
For those that have not read up on the Prodigy, it varies the amount of power going to the brakes based on inertia, the harder you step on the brake pedal the more power it sends the trailer brakes. Also as you come to a stop the controller backs off on the braking power to the trailer making for a very smooth stop.