I purchased my brake controller from the "Trailer Guy" on the Pirate board. After researching, I had narrowed down my choices to the two controllers you mentioned. When I spoke with Arron, he recommended that I save the extra money and go with the Prodigy. He indicated that while the P3 operates slightly smoother than the Prodigy, the gain would only be noticed by someone who spends a lot of time behind the wheel towing heavy loads. Hope this helps.
Matt