Dissenting voice: I worked for a full decade for an employer which exclusively provided Aeron chairs. They gave me terrible back and neck problems, even after spending substantial effort selecting the correct size and setting the lumbar support correctly. It was like sitting on a trampoline for me, and I grew to hate them.
Conversely I have, for the last four years, sat in a cheap IKEA MILLBERGET swivel chair. It has been excellent, and all my back issues have completely disappeared.