Real-time collaborative editing of a LaTeX document sounds like a nightmare to me. You would need to be extremely diligent about breaking the document up into a set of sub documents and who is touching each part of the document.
I have edited in writeLaTeX intensively (2-3 people working simultaneously up to a deadline), without any file division or section "locking" and merging was much less of a problem than with version control. The overhead was certainly lower than carefully coordinating who-is-touching-what.
* much of this was sitting in one room. Not sure how crucial that is but a shared voice and/or chat channel for before-submission sprints can never hurt.
* I'm comparing to a VC experience where most authors don't know the VC well, are afraid of conflicts => postpone update & commits (certainly don't break up commits into semantically closed steps) => get bigger conflicts and suffer more...
My sample^Wanecdote size is <10 but I'm afraid this is representative of academic users. (would love to see wider data!)
* I'm talking about collaboration where people don't have time to regularly review others' changes, just work on the current version. If you practice change review, you're better off with VC or something like Draft.
Broken compilation was a bit annoying - whenever one person breaks something others can't see their changes in PDF until it's fixed. wL mitigates it a tiny bit with editor tweaks, notably closing {} when you press {.
In an ideal world one's edits would happen "on a branch" and wouldn't be merged if they don't compile. This is hard as the comfortable real time editing latency is below latex compile time.
There is an opinion document authors don't need version control because unlike programming there is no build to break. I agree real time is better but disagree on the motivation: with documents you can't afford version control because there is no build nor tests to break; without ability to notice merge bugs, minimizing branching is your defense.
