Barbed fittings: Good or bad?

QuickDart360 said
Do brass fittings come out easier than metal fittings after time of use? Or no difference?

I would expect things to be worse for an iron manifold over time as brass is more galvanically reactive with steel and iron than aluminum.

Steel and iron are also less galvanically reactive with an aluminum intake. Any plating with cadmium or zinc will effect it too.
Galvanic and Corrosion Compatibility Dissimilar Metal Corrosion - Engineers Edge

The issue is that there is a conductive fluid around the parts all the time working to complete the electrical path to transfer ions. It is a harsh corrosion situation. Any teflon will help, but nothing can stop it.