I have a tekonsha P3, and absolutely love it! It's got a digital read-out that you can change the display color to match the ford green of the dash. It was like $139, but included the OEM factory harness that was basically plug and play with the factory harness in my Expy.
so I plugged in the harness under the dash, backed out one screw under the dash, mounted the bracket, installed the unit and was up and running in under 10 minutes.
Mine needs minor adjustments depending on load, but otherwise works great! Not to mention, I wont spend a nickel at wally world, it'll probably just get spent on chinese products, or they'll put some family owned store right up the street out of business... Where is the tekonsha made again anyway? lol