So apparently this cheaper option doesn't come setup and ready to use? It's not exactly plug and play it seems. I got chris to install his cruise control in my v35 a week ago and works amazingly well, rediculously accurate to maintaining the desired speed. Unless you go down a long steep hill which requires brakes to maintain speed such as the gateway bridge, the speedo needle doesn't ever seem to budge from the set speed through all sorts of different road conditions and speeds plus it comes already setup and ready to use, no tuning involved.
Chris installed it for me, but I watched him do it and it took all of about 15minutes from start to finish, no cutting wires, and it did come with the factory controls. Plus there was no programming or anything involved with the setup. It was as simple as plug-in and drive off.
I'm not saying that you should purchase one or the other, but I am saying you shouldn't laugh at the price difference.. as with everything in life, you get what you pay for.