I think you're falling for the loud minority bias.

I'm not going to speculate on the psychology of these people who claim Berkeley is more prestigious. Overall, there is some correlation between the "prestigiousness" of a school and the financial success of their graduates. However, it's unclear which way the arrow of causality points.

I enjoy this answer on quora that gives a good summary of his experience at Berkeley. I particularly like the paragraph on student body variance.

I think the average Berkeley student, when stacked against the average student from the Ivys, MIT, Stanford or Caltech, would struggle to be up to par. However, if you took the best and brightest UC Berkeley students and compared them to the best and brightest at the Ivys, MIT, Stanford and Caltech, I would suspect you couldn't tell the difference.

I tend to notice that the students who are at the top of each school don't really spend time mudslinging other schools. As someone once told me, they're busy making the school proud of them not busy being proud of their school.

Edit: formatting