As a part knowledge worker, I'm no stranger to sitting for long periods of time behind my computer. I figured out 16 years ago that my back pain was mostly the direct result of the way I was sitting while working on my computer. The "ergonomic" chairs that most people can afford are nothing of the sort. To achieve true ergonomics, one has to spend a bit more money. Either that, or just stand all day & suffer the trade offs of foot pain.
This chair is very well built - I bought the below kneeling chair 7+ years ago & its still kicking. It's Swedish & called the Thatsit Balans with back by Varier. So much so that I expect to gift it to my future grand-kids. I recently had a small plastic piece break. I emailed the company & they sent 2 replacements the next day! No questions about when I bought it or proof of purchase (however, I did send them a pics of the worn out part), they just supplied the requisite part. I'm definitely a fan! One super-minor drawback is that you have to tighten the hex screws about once a year as you're swaying back & forth on a real wood frame & the screws do tend to loosen over time. No big deal - takes 2 mins once a year. No regrets here!
If you're a fan of the Showtime show "Billions", you'll see a different variant of this chair in the background of Taylor's flat in season 3 episode 6. BTW, this particular chair is offered in multiple frame types, seat colors, & seat materials. It ultimately works out to be thousands of possible configurations.
While I really enjoy my kneeling chair, my next job has me exiting my chair many times per hour & entering/exiting the kneeling chair that often can get a bit frustrating. So, I recently bought this German-made chair (called the Swooper). It's also configurable to the tune of thousands. I came across it many years ago online, but couldn't find a local dealer to test it out. As fate would have it, last year my wife's doctor had one in her office. I was caught testing it out by the office secretary (whoops :) ). I was hooked. It's super extensible - it can be normal height or really tall where I'm almost standing & leaning on it.