I just bought one of those backless saddle-style stools for my regular sewing machine - I tend to hunch my shoulders up and this type of seat is supposed to force you to sit up straight.
I like it a lot...except my left hip gets really sore after only a little while. I've had that hip replaced and I think things just don't sit quite right in that area. It's really disappointing...not only was the stool expensive but I could tell it was already helping with my back! But I don't want to just trade pains... I haven't given up yet, I'm trying different angles to the seat and seeing if I can find a happy spot because I REALLY want this stool to work out. I love what it does for my back, and I love how much smaller it is than my regular office chair - takes up much less space in my cramped sewing room. And it's surprisingly comfortable overall, except for my poor hip.
