Like a lot of people on 6x6world, I had both machines. Both will go anywhere, both will crawl over obstacle and up really steep hills in high gear if the drive belts are good.
Some people like the Argo better and some like the Max.
I love my Max IV just because of the way the T-20 transmission work and the fact it's a smaller 6x6 with the rear seat facing forward. (better for the kids and wife)
I mostly use the Max IV during winter with tracks and surrounded by argos. Both will do the job.
2008 MAX-IV 500T 30hp Bandolero