Whatever style you prefer. There is no best, there are just some that fit your needs more than others.
I have an Activator III. I like it because you do not see a controller mounted in the vehicle all the time. I have the brain of the unit mounted in the dash out of sight. When needed, I plug the hand controller into it. When not used, the hand controller is in the seat pockets.
I also use the Activator controller and it works great. I pull an enclosed car trailer (pics in my library) and have had excellent performance from my Activator II brake controller. I have my brake controller user guide posted in my library if you are interested in seeing it. For the most part it's all about personal preference and how much $$ you want to spend.