My back has improved so much since getting this chair.  I sit in it for very long work hours (10-18 hrs/day), and it is very comfortable. I have fibromyalgia, and sitting for long periods can be very painful. I do not experience that with this chair.  The one thing I will comment on is that it does NOT have a tilt function for the bottom part of the chair that you sit on.  The "tilt" function is actually a reclining function to adjust how straight or far back the chair's top portion can go. I've had this chair a couple of months now and have no complaints. Highly recommend for long hours sitting.