My favorite part has been taking down convoys. It's a blast trying to catch the leader while his escort vehicles try to take you out and you're driving top-speed through all the sand, dust and car debris. And you get a cool hood ornament to top it all off. Car combat has been the highlight for me for the 14 hours I've played.
Unfortunately, the hand-to-hand combat is getting fairly tedious. I like the Batman style but in Mad Max you're severely limited by the lack of gadgets. Batman shined because you had so many options. In Mad Max you can punch, punch harder, shiv and shoot your shotgun. Just having another 1-2 weapons would have gone a long way I think. Sadly, Batman-style gadgets just wouldn't make much sense in Max's world.
Good game overall though.