Well, a couple of us are in there "Waving", heh. It's a bit confusing and hectic. People can see your typing *as* you type, so they see your typing speed, typos (before you correct them), etc. It's interesting. You can also have massive threaded conversations happening in realtime, so someone may be responding to a post way up above in the thread while you're responding to something else. Now it does mark things as unread, so you can find them, but to do that so far it seems like you have to "scrub" through the "wave" with the slider on the right. I don't see a "jump through unread messages/edits" thing. Also you can edit yours or anyone else's post (no way so far I see to mark something as not editable by others - needed feature IMO), but when you do edit, it just marks the post unread, it doesn't highlight what was edited which IMO would be helpful.
So far it's very interesting, but I really don't see a useful place for it in my workflow. It just seems too scattered, or at least too easily scattered. If you had disciplined, smart, fast people using it, they could use it effectively as a very powerful collaborative tool, but you'd really need a commonly agreed upon organizational approach, for one thing. Part of the value as well as the challenge of "Wave" IMO is that it doesn't enforce this so much. There are fewer "rules" than there are with email, chat, forum, etc.
One thing I know almost for certain: this will not catch on on a large scale if it stays like this. It's just far too scattering and hard to manage for most people. To say nothing of its practical utility in the workplace. Most people I know can hardly manage nonrealtime email communications, let alone this crazy multi-threaded thing...