High bar is for sexy people doing sexy squats. Low bar is for Americans who can't ROM. 
It broadly depends on athletic deployment, body morphology and what you prefer (yes, really)... weightlifting requires high bar for support and low bar doesn't help (as an example).
Practically, high bar squatting will need supporting by lots of pulling work; low bar squatting will need supporting by front squats or DBSS...

It broadly depends on athletic deployment, body morphology and what you prefer (yes, really)... weightlifting requires high bar for support and low bar doesn't help (as an example).
Practically, high bar squatting will need supporting by lots of pulling work; low bar squatting will need supporting by front squats or DBSS...