Yeah, collaborating in real time on the same document is pretty neat (from using google docs for this.) Having someone else typing on the same page got an unexpectedly visceral "argh! it's moving! get it off of me" reaction the first couple of times I tried it, had to switch tabs and come back later.

It's definitely only a problem for some people, and might even be specific to some aspect of the google docs implementation, I don't know yet. But yeah, that feature is not the slam dunk it sounds like, and you might not realize it until you're in the middle of it.