The 120mm and 80mm supernova are versatile in different ways.
I use both alot and love having both.

The 80mm is great for front rack, press, overhead, & squat archetype work. Allows you to be more precise with what you are doing. Good with quad, hand, wrist, feet, ankle.
The 120mm is good for these areas,& back, hamstring however, sometimes you want to zero in on a smaller portion. I use both many times.
Working globally to more specific.