If he doesn't have a good answer, you may want to keep looking. Manufacturers agree that there aren't a whole lot of dramatic differences between the various types of equipment. Except the guns. The guns are the whole ball game. The key in our business is that if you can come up with a way to atomize latex enamels, the architectural coatings, you've hit the nail on the head.
Any gun can spray a stain.
It's the guns that can spray the latex enamels that are the good systems. Buying HVLP is like buying any other piece of equipment. Go to the demonstrations and test them out. HVLP doesn't feel the same as airless or conventional, and contractors will have to get used to the difference. The more psi, the more cfm, the better your atomization will be.