All point to the fact that ergonomic research is far from complete on the benefit of specific design factors. Still, if people are comfortable and their chairs support a variety of tasks, they're probably less likely to be injured. The general direction of the standards is toward supporting cross performance through furniture that is multi-adjustable, suitable to individual employees, and easy to use. We take the politics out of seating. There's no separation between management and task chairs.
People come here to get trained and fitted for the chair that meets their needs.
The sole criterion is comfort. That is a very good question. With proper training, a high percentage of users will make some chair adjustments. That petite woman from Thailand and the large man from Tulsa mentioned earlier are not likely to find comfort in the same chair. You don't adjust your shoe every time you put it on.