@Smergen,
When looking at Brake Controllers, there are two types - proportional (apply more voltage as you brake harder) or fixed (applies the same voltage).
There have been many "religious wars" over which type of controller is better, so do your research here and on other forums and make sure you ask lots of questions.
I prefer to use a proportional controller as they change the voltage to the van based on your braking force. If you brake hard, then a higher voltage is applied to the van's elec. brakes. If you touch the brakes slightly, then only a small voltage.
A fixed controller is just that, a fixed voltage is applied to the van's brakes, but can be adjusted manually. When you are travelling on a highway, you will adjust the controller to send a higher voltage to apply the brakes a bit harder, but when you get into a town or driving at slower speeds, you typically need to turn the voltage down again - if you don't you might find the van's brakes being applied too aggressively and having the van's brakes/wheels lockup.
Again, this is just personal option and preference.
There have been some horror stories about buying cars with an existing brake controller installed, due to some dodgy work. Check wiring, age, etc.
When we were looking for a new tow vehicle, I found the dealer only wanted to fir the RedArc fixed brake controller as it is a small know and LED that fits into a spare switch panel on the dash. Again, I wanted a proportional controller, the dears would not fit them, so I had my Auto Elec do it.
Hope this helps
Ro