I ran a mack for my previous carrier, now it sits because it is to old for Panther (such is life). Mine is a midliner, the WORST for getting parts due to the fact that NONE of it is American. It is probably not a good compairision. However, it never left me walking, parts could be got quickly if needbe (most had to be fedex'd) I had 0 downtime.
Some say once you go mack, you never go back. I guess it is all up to you. Mack uses common brake systems, axles and transmissions for the most part.
Then there are those with the jokes.. Know why the dog is facing forward? So both a-holes can look at each other. Know why the dog on the hood is smiling? He is sitting on the crap, and your sitting in it.
Little Mack factoid. If the dog is gold, the truck is 100% pure mack.