I'm currently sitting on a Herman Miller Aeron.
When my last (relatively inexpensive) chair gave out I haunted the local office supply stores looking for a decent replacement. There were none to be found. Only after exhausting the search for an inexpensive ergonomically sound chair did I start looking at the ergo chairs. I was fortunate enough to be able to spend time at local dealers trying out the SteelCase and Herman Miller chairs.
I ruled out the SteelCase because of their decision to keep the seat pan level as you reclined. As I sat in those chairs it seemed though they encouraged me to slouch. Otherwise, they were quite impressive.
So I eventually settled on the Herman Miller Embody. And I really, REALLY liked it except for one itty, bitty problem: After sitting in it for hours, it felt like there was some sort of strap in the seat that was hitting my legs just wrong, to the point where it was painful. The dealer, after consulting directly with Herman Miller, thought it might have been a defective chair and sent me a replacement. It turned out that it was just how that design affected me. So I had to send them both back.
The Aeron, on the other hand, has been excellent and comfortable. I ordered the one sized to fit me (size C) and it has proven to be an excellent chair. I wish the front edge curved down more so that its support was only from fabric, and I'm not so happy with how the arms adjust. I also added a head rest to it. But this one is a keeper.
Still, if it hadn't been for its impact on my legs, I would have kept the Embody. It's full back support and movement is fabulous. And I much prefer its armrest design.
IMHO, this kind of situation is why its important to work with local dealers. Being able to arrange showroom tests, longer term in office tests, and returns is a big advantage of local dealers, making the extra expense worthwhile.
I'm curious, did anyone else experience the problem I had with the Embody?