Adhesion promoter for painting golf cart bodies

[maxim1157]

Okay this thread could go under any golf cart section, but since it pertains to my Yamaha cart I'll ask it here. I see that there are many different brands of adhesion promoter out there to use.. anything from rustolem to bulldog, 3m brand.. etc.
Is there any advantage to using the higher priced version.. most come in a spray can application as well as from a qt can to spray your application through a paint gun. Would like to get a few options on what some have used here, as well as the success they got from using their preferred products..