Get it here.
There is an important fix in this beta: a fix for iOS devices that don't show a Mac you want to sync with on certain networks. The issue was in MacJournal, but it only presented itself on certain network configurations, so you may not have seen it. But if you were in a situation where the Mac didn't show up on your iPhone or iPad even though you're sure the two devices are on the same network, this could be the fix for you.
There are also some other fixes for rare crashes, blogging to servers with a self-signed HTTPS certificate, and others. Please let me know of any issues.