Release Candidate means that the features have been locked, but some bugs are still being chased. More importantly it’s available for download.
There’s two links you want to checkout:
The fist one is the Exchange Team Blog, the second one is the download site.
The download site is taking a bit of time to come online, however what is online already is the resource page with videos and demos.
In the blog post, Michael Atalla is quoted as saying “If Exchange were a standalone business, it would be the 9th largest software company in the world”, that’s BIG, and honestly, it’s a product that I super stocked about being an MVP for.
There’s quite a bit of news in the post including co-existence options going back to Exchange 2003. I suggest though that you have a look at the documentation that’s available as it’s getting better and better every day.
Well done to the Exchange Dev team!
Happy Evaluating.