Top tier: ML Campbell, Milesi, Centurion, Gemini, Chemcraft, Renner

Second tier: Ben Moore's has Advance and Cabinet Coat. Sherwin-Williams, ProClassic.

These are the brands most cab painters use.

If using quality product, there's no need for a clear coat - I would need more details and clarity about their process.

Painter B is obviously a house painter, not a cabinet finisher. No one knows about A, without listing the actual specs of the work, and the actual finish material being used. But, if they aren't at $150 a door +, then they aren't cabinet finishers.

Ask what product they're using. I think you need more quotes. Ask the sales people at BM who they sell the most Advance to. This is an explanation of how it can be used.

Advance is a trim paint that homeowners use for cabinets, because they can brush and roll, and it stays open long enough to allow that. And it stays open long enough to get all kinds of dust and trash in it. And get touched and have permanent fingerprints, etc. Professionals spray cabinets, and they also use materials that do not take a month to cure. They don't have 24 hours to wait to flip the doors. They can flip in an hour, with a professional coating.