I'm going to go a bit against the grain here ...
I had a set of cheap guns which were not working well. I had a goodcaircsupply with filters and water traps. My projects are all over the map - I've shot wood working with latex, oil based, and lacquer; metal work includes enamel single stage, metallics, and base+clear.
I walked into my local classic car hot rod restoration shop (doesn't everyone have one of these in their town?) - a father & son business which also is the only paint supply in the area.
I asked the question, "I need a new paint gun. I have a cheap one and its just not working. What should I get?" The father had a noob in his midst and could have made a nice bit of change.
He asked what I was doing; what problems I had; and how I was prepping and cleaning the gun. Then the bomb ...
He pulls out a $34.50 gun, in that environment destroying formed plastic display packaging. He said, "I could sell you a $400 gun but this works. It's what I use." Then he took me into their body shop and he showed me how to set up the gun and how he cleans it.
I've had that gun for two years now and it is still shooting great. I know that my latex projects will kill the gun in another year or two but I won't worry given the price. If I were only shooting fine finishes, it would likely last me a decade or more.
I'm pretty sure it's
this one .
You can see an example of clear over base / metallic here ->
http://vimeo.com/50006571