I had an el-cheapo controller from the local farming store and towed to Atlanta with it. It puked when I got into Atlanta traffic, ultimately resulting in me nearly rear-ending a semi!! It was not a good trip.

Three days after I got back, I ordered the Tekonsha Prodigy. I will never go back to the other kind. Not only is the brake controlling really good, but it tells you what is going on in terms of connection, ground fault, etc.

Yes, it's a bit more expensive (close to 2X the other one, iirc). But, like a good helmet, the price is small with the peace of mind you get.