A question before my own story: What does everyone do as far as trying out chairs? It's crazy to me to base my buying decision on 10 minutes of sitting in a store. Are there stores out there that allow for in-home trials of these products?
One of the thing that always amuses me about "best chair" recommendations is that it's an entirely personal choice.
I am 6' 2" and 200lbs. Understanding even more than that about the size of a person is critical to understanding their needs in a chair. No matter how adjustable a chair is, it's simply not going to be best for everyone.
At home, I own a size-C Aeron chair that I purchased in 2007. I love it and the only thing I've ever considered is upgrading to one with the highest-end back support rather than the standard lumbar cushion.
At work, I sit in a Steelcase Leap. It's certainly a fine chair and I have no real problems with it. I find it very comfortable and I'm able to sit for much of the day in this chair without any issues.
My gut tells me that I prefer my Aeron; that said, the more I think about it, the more I realize that I've never questioned that assumption. The one thing I know is that I do prefer the breathable material on the Aeron.