Leaving aside the ridiculously overpriced chairs, I'm quite fond of mesh ones like
this one. They are super comfortable, adjustable, and (important to me) they stay nice and cool on warm days. No swimming in a sweaty seat. Also plenty durable - I was dubious at first that the mesh would hold up, but my ass has been planted in this one for hours a day, every day, for ~4 years and it hasn't altered shape or lost any support. I love it so much I talked work into buying me one for the office.