Rattle can is rattle can. If you can find the color you want in say krylon or rustoleum enamel, your are getting the same product.
The appeal for them mixing it up is to match a color that the rattle can industry does not provide.
If you just want say... argent or black, buy the rattle can in Kyrlon or whoever.
1K paint is junk no matter what you pay for it. Here is some good info
http://www.eastwood.com/1k-coating-vs-2k-coatings