Not to sound harsh, but this is a terrible idea for so many reasons.
1) The size of your Dropbox directory will balloon as you work because Git needs to save data on the entire history of your work. 2) If syncing sucks, why not just push code to a normal remote Git repository hosted by a site like Github, or even your own server? 3) He says that it helps for collaboration, but then says he only uses it for projects where he works alone. What?