Both J-Max and JX-Pro grinders are overall grinders that could brew for several methods.

The Titanium-coated burr design of J-Max and the Stainless-steel burr design of JX-Pro grinders are different. 
The adjustment design of J-Max grinder is the External adjustment as 90 clicks per rotation, 10 clicks per number, 8.8 microns per click whereas there is the Top adjustment design of JX-Pro grinder is 40 clicks per rotation, 4 clicks per number, 12.5 microns per click.  

The Magnetic catch-cup of J-Max grinder allows you to remove it in a flash with the capacity of 35~40g.
The capacity of the Classic catch-cup design with JX-Pro grinder is 30~35g.

Both grinders are the overall grinders for several brew methods and are ideal for espresso brewing,
J-Max grinder allows more minor clicks to explore the sweet spot of the espresso compare to JX-Pro grinder.
J-Max grinder produces more fine particles compared to JX-Pro grinder.

J-Max: 0.0088mm < JX-Pro: 0.0125mm

The Cylinder case is pairing with J-Max grinder.
The Cylinder case or the Travel case of JX-Pro grinder could be select with extra bucks.