Paasche H series single actions worked well for me, but then I traded it for some kits and bought an Iwata. I get much better results with the Iwata.
All I do to clean is remove the needle, wipe it down with lacquer thinner, lube it, and reinstall. Wipe the bowl out real good with lacquer thinner. Remove the nozzle and wipe with lacquer thinner. Bing bang and maybe a minute later, it's clean.
For painting different colors real quick, I just blow any paint out, shoot some lacquer thinner through and change colors.