I dont agree with the fact that $900 chairs are magic, and $200 chairs are not. I have never bought a chair more than $200. I am using chairs that are many years old - and they havent fallen apart. I have used chairs that cost over $1000 at work. It didnt part the seas, it was just a chair - with more adjustments.
From my experience - $900 chairs will NOT: - cure your back problems - make you code better - make your startup successful
But they WILL: - make your office more luring for staff (which is very important!)