Might be a fad but I love mine, I have a spinal condition that makes standing for (most) of the day much less than painful than sitting. (so I built myself one to solve all the usual problems, 21sq/ft of space, goes high enough to be suitable for non-midges, completely and totally stable, in hindsight I might have got carried away a bit http://imgur.com/a/H7fxb - the chair is in the process of been replaced with a stool (that I'm also building))

http://imgur.com/a/H7fxb