What I liked.
Google Maps integration
I was able to add a map and plot the route on it along with the location of all the huts.
The ability to play back the history to see how the wave evolved.
I could see other peoples edits as they happened
One of the really bad things about emails is that once you send them it is to late, you can't edit them you can't fix mistakes.
It's invite only
It's still only a preview (there are still some problems to be worked out)
You can't remove people from a wave.
You can only communicate with people who have signed up.
But the real big problem with Google wave is that Google is promoting it as a replacements for email. If Google wants it to replace email it must have a credible migration strategy. Google wave is not backwards compatable with email. You can not send an email from Google wave and you can not receive email on Google wave. What that means is that as long as people I know still use email I will have to check both email and google wave. To be honest I can't be bothered, so I will be sticking with email until google wave works as an email client.