I've had my zero gravity 'perfect chair' from 'The Relax-The-Back' store since 1999.....so 17 years.
mine is a narrow 'tall' version with visco elastic foam and all the head rest surfaces and back rest curve away from my ears so it does not change tonality.
a zero gravity chair is a 12 hour chair, I can sit in it indefinitely (at my ideal listening height) without my back getting stiff since my weight is distributed over the length of my legs and not on my tailbone. OTOH an Ekones Stressless chair (a 2 hour chair) requires constant change in position to avoid a stiff back......and most of those positions are not the ideal listening spot.
I've owned a number of Ekones Stressless chairs (and have an Ekones sofa in my listening room) and am sitting in one now watching football. most of them are not 2-channel audio system friendly since they 'cup' the sound which does wreak havoc with tonality.
so pay attention to the head rest portion of the Ekones chair to make sure it does not have an inside curve around your ears.