The new version reset my Control Bar modules but that only took a minute to re-do. I haven't spotted any other issues.
The PRV now has a dark background, so as Meng said, easier on the eyes. Clicking on 'Help/Documentation' there's a page saying the manual hasn't been migrated yet with links to it elsewhere pro tem. 'Help/Support' goes to a support link all in place. And as others have pointed out, I'm a 'member' for six months to 4th October 2018.
I loaded a project from yesterday (the recent files were all still showing under 'File') and nothing burped. So, all good so far. I bought full Melodyne and Addictive Drums so I can't speak for those that had the 'included with Sonar' versions.