There is, however, one "problem" that prevents me from switching to c9 and trying it out for a few days: as far as I can tell c9 allows us to edit files on your server and then push the updated project back into the git repository. For a web dev like me this would mean a commit after every edit and then I'd have to manually pull the changes from GitHub onto my dev server every single time.
I don't know if I'm the exception here, but I pretty much need my editor to save files directly onto my server (preferably via SFTP). The git integration thing is still great, it's just not compatible with my workflow to do a commit and manual pull for every edit. I don't spend hours making changes and then test them all at once - instead I make small changes, save, and then run tests immediately.