I agree with the chipping part but it has way more fill properties than a 2k, and a 2k is way more finicky. It also sands better than 2k's hands down. I think poly primer is best served for getting it straight with two rounds, or however long it takes a person, THEN top coat it with a 2k primer for your final sanding.
It sprays fine if you know how to use it. His problem with it is not the product, I can guarantee that.