The x max 120 is the best all round option in the x max range I think. Th flex is responsive without being too stiff and can be adjusted down to 110. The boot out of the box is low volume with a 98 mm last and low instep and heel. However the shell uses full custom shell on the clog meaning a lot of the fitting work can be done very easily. Like any custom shell boot always get footbeds made before moulding.
The boot uses the race liner which features mouldable foam on the outside of the liner to help the liner mould to the shell giving a very solid fit.