Haven't been in a while, so first of all Hi!
I stand at work everyday, built my own standing desk by modifying the office supplied one. Sometimes I sit to break things up. Even standing can have problems I find. I started standing coz my arse started getting shaped like my chair
Joking....My tailbone did start getting very sore from sitting so that was my initial motivation. It has helped a bunch, soreness only shows up when I go back to sitting.
Going back to the problems with standing for a moment. I can be so lazy sometimes I'll stand leaning with all my weight on one foot for hours sometimes without even thinking about it. You guessed it, my foot gets sore...doh! Got to remind myself to move around once in while. I've taken to keeping a broom stick at my desk and I'll grab it every now and then to do some OHS form stuff. Pretty nice, keeps me loose and relieves a lot of tension too.
There's a guy here who does sit on one of them bosu things. First time I saw that I said "hey, you're sitting on a ball" and the reply I got was "yeah, it's good for my 'roids".