I just had the MC cruise control installed on my bike by my dealer. He became a licensed dealer due to my request and mine obviously was his first install. It took two of them 6 hours (I have the Corbin bags and they had to be removed and replaced) so it is not an easy do-it-yourself task. I drove my Spyder for the first time this morning, using the cruise control on the Interstate, and it was wonderful.
While some might like the Audiovox and the MC does come at a hefty price, the MC is made for a motorcycle. The Audiovox is made for a car, to be installed INSIDE a car, safe from weather. The MC is made to be outside and is water resistant. It has all sorts of safety features - I can cut off cruise by hitting the throttle, hitting the brakes, turning it off (obviously), and even pulling in the clutch (not the preferred method). My dealer even tried it in different situations such as taking a turn too fast, and with the MC connected to the Spyder, the two sensed the speed, and the cruise shut off.
It's just a matter of how much is your safety worth.