I rocked the Aeron for a few decades. They still work for me, understand they come in 3 sizes and a few features are optional -- particularly if you buy them for $400 from a liquidation. I switched to an Embody recently and while I like it, it doesn't have the "all day" ness of the Aeron. I know "all day" sitting now is akin to chain-smoking 4 packs of unfiltered marlboro reds, but... here I sit anyway.
I've had companies that used the Steelcase Leap and people love them, but I could never find the all-day settings for myself, despite a few Ergo "fittings". If you're in the >$1000 MSRP space, you'll want to test-sit all of these or pay a little extra and buy from a place with a generous return policy.
I'm big+tall and anything less than a quality chair is grist to my ass's mill and will be trash in 6 months.
$0.02