On the rare occasion that I do latex, I use a Graco 395 airless. It's a serious pain to clean, set up, spray, and clean again...but I've had one hell of a time trying to get latex to work with a cup-gun or my HVLP turbine sprayer. If you use an airless, I recommend having separate hoses, guns, and suction lines for water and oil base products. I had problems with little bits of oil winding up in my latex after it was sprayed and it caused fish-eyes.
I've only brushed poly, or used a store bought spray can.
I am by no means a pro with this finishing stuff, and the one time I did a latex paint grade kitchen I nearly lost my butt due to fact that each door needed 4 to 8 coats of paint until I wound up with one coat with no defects. I will never do latex on wood again. Colored lacquer is the only way to go. It sprays like any other lacquer, dries enough to sand and recoat in about 45 minutes (at 65 degreesFH or more), and will have no reaction with a final coat of clear lacquer.
