This is heading for the basement. Surely my less-than-happy experience isn't the only opinion out there?

I'm not completely opposed to CNG at all, just that duel-fuel gave me a couple of worrying moments in a car that was basically tuned for petrol. The weight problem was a matter of bad distribution.
Refuelling was more complicated that petrol, but the whole thing was much more sensible (to my mind) than purely electric cars.