I recently switched from Pro to $100 Max, and the only difference I've found so far is higher usage limits. Antropic tends to give shiny new features to Max users first, but as of now, there is nothing Max-only. For me, it's a good deal nonetheless, as even $100 Max limits are huge. While on Pro, I hit the limits each day that I used Claude Code. Now I rarely see the warning, but I never actually hit the limit.