Originally got this as an exercise ball but it quickly replaced my old office chair. For the first 1-2 weeks it felt weird I admit. But after that it was my new normal and I definitely don't regret it. A fraction of the cost of a decent office chair and ridiculously comfortable to sit on.

Some people wonder if I find it annoying to 'balance' on for extended periods of time. No, not at all. I've sat on this as my office chair for almost 2 years now. That's crazy to think about. I filled it with air once. I have not felt the need to refill it until recently (haven't done it yet). So after 2 years of sitting on it daily and using it as an exercise ball I am just thinking that perhaps it's time to top it off.

I recently took a motorcycle riding course and sitting on an uncomfortable hard moto seat for 10+ hours. After that it felt like a train ran over my ass. I couldn't imagine having to go home and sit on a hard office chair but despite the pain this exercise ball was nothing but a relief to sit on. Too bad the motorcycle seats can't be this comfortable.

I can't say I have a single complaint about this ball. Normally I can find something to suggest room for improvement.

All I can say is that I'll never buy another office chair for myself again. It may look stupid and ineffective but I've found it's the complete opposite for me.

Side note, my usage is on carpet. Have not tried other surfaces.

Ended up ordering this one in the largest size, because it was one of the few that I (5'10, female) could sit on comfortably allowing my knees to be in line with my hips. My husband is 6'4 and can also sit on it without an issue

Currently 9 mos pregnant and using as a bouncing / rotational ball to help induce labor!

I am a PT and I am using it for treatment. The inflation took a while, but was easy.

The air pump is weak, couldn't fill the ball fully, had to use a bicycle pump

I like the size, works well for me,even though I'm shorter then what they recommend. Good value . I highly recommend.