That is a WEIRD looking chair! Particularly the one that you sit on sort of backwards, with what looks like a back rest actually being a chest-and-forearm rest. It seems like that would be hot, like wearing a huge padded vest.
I would be curious to try one out...I have back problems, and have had a hip replaced, so not sure if it would be really good for me or really bad! Where would one go to try one out in person, I wonder? I've never seen a chair like that for sale around here.