I used vision and had no problems with it, but I was impressed with Dave's testing and use of gg4 also, and no offence to the vision guys Titan labs have been in the chemical game longer. Then yes the price has to be looked at as well with 4 vans bringing filled per day.
As for pure water, it's great, but I will repeat what I noticed (and a few customers) that windows washed 4 wky over a period of time (eight months or more) never seemed to shine like they did in the early months with vision or gg4 this brings back the shine - pure water is a great cleaning agent but over time produces a dull finish to frames ( if you wash your hands with pure it seams to strip you of natural oils in the skin ) an additive restores this, my water still reads 000
Darran