The hi-top offers the most fire protection, but can restrict ankle movement and fatigue your ankles and calves from working the pedals. An easy solution to this is to leave the top loose. A full Nomex interior is nice, but not too much padding as this will reduce sensitivity. Some shoes use a soft rubber sole. This gives great pedal feel, but fatigues your feet as the pedals dig in.
Good shoes have a sole that is thin but stiff.
Some even use a carbon fiber plate. This allows the sole to be extremely thin for maximum sensitivity, but also very stiff so pedal pressure is distributed across the entire foot. Some use a leather pad sewn on the right side instead of an extension of the glued rubber sole. This prevents it from peeling away under heavy use. There are many accessories to be aware of.