First the gun - I have another version like this (for cavities and with a cup) where the trigger handle often misses the trigger pin - this gun worked fine. Yes the handle could be better, but otherwise it worked great. The undercoating itself does not go far. I used 3.5 of 4 cans just to do 4 wheel wells (3 coats). Final thing to watch for is don't go too heavy - I have 2 coats of DTM Epoxy, covered by 3 coats of Acrylic Urethane. In a few small areas where the undercoating went on too heavy, it lifted the paint - couple places down to primer, and in another couple places down to metal. I find it hard to believe it was a prep issue as the locations were not out of the way, so I assume the solvents in the undercoating got trapped between coats (heavy spots) and caused the paint to lift there. Luckily the areas were visible, and easy to repair after things thoroughly dried. Just be careful.