For legit feedback you need to design a blind controlled study where subjects will drive 2 trucks (one with HHO and one without) on the same route, for the same distance, with same driving habits. The study would have to last for a considerable amount of time to ensure that the results are not influenced by daily driver and route variations, etc...
Than you can compare the results and give us all a legit feedback. :biggrin2:
Otherwise it's mostly anecdotal evidence, similar to the results of adding acetone to the tank-full: some swear by it, some had no improvement.
Besides, it's Saturday and it's 95F here. So I'm going to get myself a cold one. :biggrin2: