By the way, I don't think student pilots are able to judge the quality of their instructor in the first place. Looking back now I'm an instructor I can tell wheather my instructors where good or not. But definitely not judge before you have experience yourself.
A lot of students blame their own inability on the instructor and the school.
But in the commercial world we do not really have an option to be honest and just say you don't have the ability, find another career.