If you brush roll or spray it on out of a gallon or qt its still just a better coat of a cheaper paint.
If the Primer isn't Epoxy Primer it has a good chance of absorbing moisture over time unless coated in an enamel, or acrylic etc, type of paint... or clear coated.
You could look at it this way:
What does this truck mean to me?
And if it was a chick, where would I take her out to dinner?
I'd guess Rustoleum rates about equal to IHOP or maybe Denny's vrs something fancy in Paris.... France not Texas.
That leaves Memphis, OKC, St.Louis, and New York city in the middle. They ALL have an IHOP but the local flavor shifts.

There are some really good threads 'out there' and in here that cover getting the most out of the chea... least expensive paints and how to improve them and their use.
Maybe turn it into your own experiment?

From my experience about the only place you can really find 'Fun' doing body work and painting is in the choosing what your gonna do dept. dang So I hope your having fun now!


Give me ambiguity
or give me something else