89 F250 Custom. In the process of giving it a tune-up. Is there a major difference between Motorcraft, MSD, BWD and Duralast? This would be for a cap rotor and spark plug wires. Don't know if this makes a difference but the truck is rarely used.

 

I would go Motocraft
It is Genuine Ford parts and Ford has spend thousands on research and quality control. Stick with what has been proven true and you know will work.
Just my $0.02