Really, more than anything it's the sequel Road Warrior that is a true classic.
Mad Max is basically a small Australian cult film that you either get or don't get. I "get it" and love it.
Road Warrior is a true classic, on par with Terminator 2 as the best of the old action flicks. It's simply called that in Mericuh as the execs felt the original cult classic was unnecessary. Meanwhile in Australia it was "Mad Max 2".
Mad Max Beyond Thunderdome was a miss. Amusing enough, but nowhere near as good as the other two.
Mad Max Fury Road is another real classic. On repeat viewing, I'll probably like it better than Road Warrior.