What are the advantages and disadvantages of wobble chair over exercise ball used as alternative (supplementary) chair for prolonged sitting at the office desk?
(Tip: with exercise ball you will get your pants dirty.)
The link you included showed armrests, which would probably help reduce shoulder and even neck strain, as ergonomically speaking, you'd want your arms supported if you're typing.
The wobble chairs I have experience with have some ways to adjust them, which means you can fit them to your stature. This is a good thing - an exercise ball might not put you at the right height for reaching your desk or viewing a computer monitor.
Disadvantage of a wobble chair would be price - they're definitely spendier than a simple Swiss ball. And because they offer more support, you don't engage as much muscle to maintain good posture. But since most people have horrible posture, they need the extra help, so while it may seem like a con, frankly I think this is a pro.
In the end, I'd say a wobble chair is a better bet.
Working at a high tech software company, I am constantly on the computer writing code, so anyways. One of my colleagues brought in an exercise ball, after sitting on a wobble chair for a while. I borrowed it the other day and sat on it throughout the whole workday. It is definitely a good way to keep your "core" stomach/abs muscles constantly in check/activated, because you constantly in balance and in good posture (or else you fall).
Wobble chairs vs Exercise ball, I'd vote for Exercise ball ;)