I have used it, but I have never used the supplied soap, which those who have complained that it left a film on the car (windows particularly). My complaint with it is that the (deionized) water flow is so anemic, and that I have bought cartridges that malfunctioned and clogged up right away. The idea is good, not so sure about the execution. I believe some have put "regluar" car wash soap into the gun; the Mr. Clean soap has extra sheeting agents in it to get the water to run off the car, which is what leaves the film, apparently.