I plan to share my own impressions later, but for now, here are some of the innovations in Logos 5. (I think their servers are groaning a bit right now.)
Here is a link that starts you through a series of vids on specific features of Logos 5. Let's single out a few.
Here's an overview of new features:
It comes with a nifty memorization tool:
The exegetical guide has been enhanced:
One of the pretty amazing new tools is the Timeline. Check it:
Major omissions, however, include birth of Phil Johnson and Frank Turk, and the start of Pyromaniacs. But that's what upgrades are for.