For the money - the Chinese.
BUT!! ... ... ... . paint materials cost so much and it's so much work to get to the point of putting on the color and clears that I couldn't recommend one to someone as their only gun.
It's mostly the color that's got to go on smooth and when you're under the clock having to get each stage of the job on right within the previous stage's recoat window you can't afford any confusion (at least no more confusion than is already built in to the game) or surprises. By the time you're doing the color coats there's too much at stake.
So. Pros need Sata guns, or the equivalent. For them time is money and they don't make amateur mistakes. An amateur doesn't need a Sata becauseowning it won't prevent the mistakes.
I'd say get a good gun of medium price for color coats and use it for clear coats too. Try out a cheapy for coating primers, especially guide coats that you mean to sand off, or mostly off, anyway. If after some time with it you feel like the cheap gun will do as well as the better one (which is kinda' where I'm at) then maybe get another one and call it your clearcoat gun.
Painting is a major PITA. I've got a lot of respect for people who make a living doing it but I sure don't envy them.