I can say that they are great for long lines. Have had one for many years. Have not used it much the last few years as I now hand pull all of my lines, but it is a great tool with a bit of practice. I could not use it doing any type of sharp curves, but you can pull a 12 foot line down the side of a car in 15 seconds if you have the hang of it. Can't say that I used anything other than one shot in it. Tried HOC striping enamel in it and it was too thin. Made a mess. (Could have been operator error!) Cleaning is no big deal either. Just takes a bit of time.
TABG
Airpower Art Studio