Please note that it took me a whopping 20 seconds to figure out that:

1] Yes, version 5.0 does NOT open the 4.x databases automatically.
2] Yes, just IMPORT it as a GEDCOM file.

Why is this good? Because it doesn't change the existing 4.x database. By importing it, it's creating a new database using the previous one. Remember that this is a BETA.

As for usability and feature feedback, I'll save that for later... :-)