I still use a HM Aeron that's about 12 years old. Surprisingly it has held up well. They aren't super comfortable but I like the fact that it breaths. My kids have Aerons also and sit in them way too much. They love them. My wife likes Humanscale (she has one at the office). The Steelcase Leap is popular also.

Everyone has their preference. I have heard 24 hour chairs are the most comfortable but have never tried one. They are typically used in environments where someone will be sitting in it 24/7/365 ( http://endura-gsa.com/ )

Here's a site that might save you some money if you're looking to buy a task chair. I think they might be refurbished but I'm not sure. The prices seem good.

https://www.madisonseating.com/

You can always try FB Marketplace or Craigslist for a used one and save a few $$$.