Upgrade went fine for us. No issues. The installer fixed all possible issues it found automatically.
Only 3 issues we've found until now.
1. The Configure and Design option under Info Center was missing. This was fixed by support
2. The KAV Profiles failed to load from the database, loading them or creating a new one resulted in a very long and boring error message. This was fixed after applying hotfixes and reapplying schema.
3. In some modules (like KAV, Agent Procedures, and a couple more) not all the views are displayed. In Policy Management some views are displayed more than once. This is not yet fixed, but might be fixed tonight after I run the newest KInstall on the server. If not I will create a support ticket for it.
Other than those 3 minor issues everything is working great and faster than ever. Kudos to the dev team.