I went to Brooks Bargain in Wilmington, MA, to get a used Aeron chair for about $500 if I remember right. They had a ton of different kinds of chairs to try on site. I went there torn between Aeron or SteelCase.
I’ve heard good things about Granite State Office Furniture too, if you don’t mind hoofing it up to Manchester NH.
Steelcase vs. Aeron is mostly about preference for fabric vs. mesh. Though Hermann Miller also has other models that are basically stripped down Aerons or don't require as much personal adjustment.
I’ve heard good things about Granite State Office Furniture too, if you don’t mind hoofing it up to Manchester NH.