best paint for exterior?

[guypm]

In your expert opinions folks, what paint would you consider the best quality in a base coat/clear coat ? My painter bought a gallon of something i've never heard of and said it is a good quality, custom paint. My interior is a PPG one-step paint which looks good. I only want to do this one time and was wondering if ya'll thought that you are only buying a name when you buy paint ? The painter said that he could use this paint on something else if I wanted PPG. He said this paint was only $25 a gallon cheaper than PPG and that he used it all the time. I cant verify this and have some doubts cause im very paint inexperienced.
Any info would be appreciated.
Thanks, Guy