For MTB, I find that the added price between low- to mid-level is worth it. I had a Bontrager low-level BOA shoe (Foray) and exchanged them for the upgraded Cambion model - much better. Why?
Compared to road shoes, the smaller cleat means more localised pressure. The Cambion’s stiff sole is more comfy since I don’t have that hotspot under the metatarsals.Many companies only spec the decent rubber outsole on the higher-level shoes. The Foray was awful, it was slick as ice on rocks and roots - whereas the Cambion allows me to hike-a-bike without fear. Shimano’s mid-range also has Michelin rubber rather than cheap-slick stuff on the lower-end shoes.