I also recommend Steelcase as a good alternative. I considered the Leap but eventually chose the Gesture, and am extremely satisfied.
Expensive artwork and overpriced lounge furniture don't improve productivity or morale. Proper work-chairs and desks, on the other hand, pay for themselves quickly.
Highly recommended.
(I researched and sat in a whole bunch of chairs, including the Aeron, before choosing the Leap.)
i bought mine new in 2006. the mesh tore and was fixed under warranty around 2010. one of the back supports broke in 2015 but they wouldn't fix it for free so i just zip-tied it and it's fine. herman miller's warranty service ain't what it used to be.
the best move is probably to buy a lightly used one at half the price, mirra or aeron.
The problem with Aerons is the mesh seat. Because you sit on mesh there is a hard plastic rim. The front of that rim press up into your leg on your thigh. It restricts circulations which can cause outright pain.
The severity depends on your body and how you fit in the chair exactly. But it's bad enough for enough people that I recommend people avoid Aeron; with the Steelcase Leap being my current chair of choice.
https://www.steelcase.com/products/office-chairs/leap/