Check out Codebox.io, another open source web ide. I've been comparing the two from a self-hosted standpoint. c9 definitely has the more polished interface (for instance, the ability to resize any pain), but codebox doesn't seem to limit any features on the self-hosted version. It just seems to work better.

I only got my self-hosted version running last night and couldn't seem to spot a "chat" option (had two different browsers open) but for any file that was open by two people, you got to see who was editing what within the file.

When I was running c9, I couldn't even get the console to display. I found a plethora of issues in their github issue tracker of other people with the same problem, as well as code suggestions to fix it, but virtually no response on any issue from the c9 people.

I reported an issue I was having with codebox on their tracker. First I thought it was a bug, then I found a workaround (set the USER environment variable before starting codebox). I reported that on the issue, suggesting a documentation update, and within an hour, they had committed new code that made the workaround unnecessary.

So for self-hosted, I think codebox has the more stable and actively developed codebase while c9's open-source version is more of an afterthought. But I do admit that c9's hosted service is much nicer than codebox's hosted service.