As I have said it many time, they are poor chairs. The people saying they are great chairs are people are coming from £30 argos chairs or £50 "executive" chairs. So of course they are going to feel like a throne in comparison. But pale in comparison to a proper chair.
In reality they offer very poor support, poor build quality. and are not designed for long use.
The fact I now have a Herman Miller suggests we might have similar outlooks and also being 45 years of age and not the whiper shapper I was, **** chairs show themselves more. I also work from home many days a week and spend perhaps 16 hours in it (or did its now sitting there for someone to take away).