I have learned over time that about 90% of the time when a fellow TDR member posts a "which one should I buy" question he is not really looking for objective advice but is more often looking for reinforcement for the decision he has already privately made or is leaning toward due to budget considerations, past experience, or other personal reasons so I try to avoid recommending a product.
I own a BrakeSmart and have nothing but praise for it. One of it's great advantages I think is that for someone who constantly pulls different trailers with widely varying weights and stopping ability like I do the BrakeSmart never requires any adjustment. It causes the trailer brakes to respond to the pressure I apply to the service brake just like the truck does. I am never surprised. If I press the brake pedal I get perfectly controlled, perfectly matched and modulated braking.
The former company that manufactured the BrakeSmart controller and now Dr. Performance will also answer your technical questions regarding the performance of their product. I have not had any warranty issues with the current unit I have or any problems whatsoever after close to 200k miles of use but the previous manufacturer replaced my controller twice without complaint or question when I experienced minor problems early in my ownership experience. At one point I had a problem with the controller, I think the digital display went dark, and called the previous rep on the phone. I explained that the truck was in use and I couldn't do without a brake controller while I shipped it back to him for repair or replacement. He mailed me one by priority mail based on nothing but my word over the phone and I removed the one I had and mailed it back to him, with prepaid shipping if I remember correctly.
I have never done business with a better company or experienced a better product. The BrakeSmart and the customer service behind it ranks right up there with Cummins engines in my opinion.
Harvey