Art, you are always busting my chops, keeps me on my toes I guess.
Most Rv'ers have just given up, cheaper and less frustrating when you just wait for the toilet burping.
My system has gone out of calibration, so I would not recommend spending tons of money on any new system. I have not tried that one, so can't say. Logic would dictate that an outside sensor would be good, but there are few systems that people like, and none that RV builders use.
Tells us something, I guess.
But what do I know, I can't even order food...
Just kidding Art...