I'm 5'10" too and have an average build! I had terrible back pain from my Office Max chair so I tried the Aeron, Mirra, and Embody. I didn't like any of them. I

I'm 5'10" too and have an average build! I had terrible back pain from my Office Max chair so I tried the Aeron, Mirra, and Embody. I didn't like any of them. I was about to give up, but then I tried the Steelcase Leap v2 and it was perfect! I purchased it ~6 years ago and haven't looked back. I think someone with a stocky build might prefer the Aaron since it has more seating room, but for my build the Leap is perfect.