I'm very happy with my Steelcase Think. I've had it for about three years now.
As others mentioned I'd also suggest optimizing other parts of your setup: desk height, keyboard height/angle, keyboard itself (I love my Keyboard.io Model 01, monitor height, etc.
Surprised to see that yours is the only mention of the Steelcase Think!
I’ll add my 2c. I’ve had a Steelcase Think since around 2012. Every other chair for me before that (including an Aeron) led to back pain - this “fixed” that problem for me, although of course ymmv.
I’ve had almost 10 comfortable years in that chair. Recently the gas cylinder finally gave out, but Steelcase replaced it for free - including sending a technician to my home to do the work - notwithstanding that it is out of warranty.
As others mentioned I'd also suggest optimizing other parts of your setup: desk height, keyboard height/angle, keyboard itself (I love my Keyboard.io Model 01, monitor height, etc.