I have three of them. One at work, one in the car, one at home. Love it, love it, love it. I actually credit it for being able to move around as well as I can.

Having said that, you will either love it or hate it. Are you attending a quilting retreat any time soon, because probably someone will have one and I'm sure will let you try it. No matter where I go there is someone who asks if they can use it for a little while. I think about 25 percent love it. The remainder hate it. If you have an exercise ball and sitting on it gives your back some relief, I say get it now, but if you aren't sure try to borrow one for an hour or so and see if it helps.

amh

I bought one and didn't care for it. I thought my rear was too big for it or something because as others say it was wobbly, so I put it in our quilt guild auction.

I have had one for many years and love it! I only use it at workshops and get-a-way weekends when my chair is not the correct height. It definitely helps. Before I had one, after a quilting weekend, I walked around like something was shoved up my dupa, due to the chair being too short. My back was literally out of wack due to long hours of sewing with a chair too short. Its worth the money.

I usually don't try things like this but I did as I have back problems and it was suppose to help (NOT). I do not like it at all, it is very difficult to sit on and actually my rear end goes numb sitting on it. Hope this helps, I have heard some love it but for me it did not work.

i know of them being used in schools with kids with attention issues. apparently, the stimulus of having to adjust self etc. helps get mind focused so it can work on other things.

I have one and use it from time to time, especially on wooden or metal chairs. A friend with back and neck pain came to sew with me recently and she used it on top a wooden chair and said it helped a lot.

If you sit on one and wobble then you could definitely benefit from using it. If you wobble it shows that you don't have core stability. Even if you have core stability you need to take a break every so often.

Sit upon
 

I bought 2 of these a cpl. of yrs. ago when we talked about them & pd. more than this for them. I find them to be miserable. Those little nubbies seem to hurt my bottom. They aren't big enough for my bottom either which doesn't help. Yikes, I can't believe I told you I have a big bottom. LOL. At least broader than 13".
My 6 yr. old g-dtr. loves using one as a booster at my dinner table so it wasn't a complete loss.

I don't have the Gypsy. I use my exercise ball. I was using a hard bench, DH offered to buy me a chair for Christmas. We even went shopping but I couldn't get my head around the price of what I liked. Then we realized I would need one of those hard plastic mats under it to protect the carpet from crushing.
We both hit on the idea of trying my exercise ball. It wasn't getting a workout anywhere else! And I had recently started using one at my desk at work.
So far, I like it, but have only used it a few hours in total. Obviously, I have to be really careful with the pins!
Just an idea. I do notice it makes me get up and move around more at the office at least.

I'm a dental hygienist and I have one at work and one at home when I sew. At first I didn't think it made a difference, but now don't want to be without it. I see a Maximized chiropractor and he gave me the balance disc for work and I feel it helps alot.