The company I work at has Aerons, and so I've sat in a lot of them over the past twenty years or so. They're moderately comfortable, but ALL of them (yup, all) have broken in some nigh-impossible-to-repair way. Typically, the control that controls the angle of the seat breaks, and then it's at some crazy uncomfortable angle, and I have to find a new one.

I should point out that I'm not heavy at all, nor am I hard on chairs!

Looked this problem up on YouTube, and found that in some cases, it's an easy fix, but not mine.