I just upgraded to 4.0.3 (from 4.0.1) and discovered that many settings I had set into the program were turned back to the default values.
For instance, most of my normal ripping settings were changed, and I only realized after ripping a few CDs, and now I need to rip them again.
The location I had chosen was changed to C:\My Music (a folder that didn't exist), and the quality was reverted to the very bad 128VBR.
Also changed back is the filtering I had put on the media tree (the tree nodes I wanted and the Collection options), and the default view.
All in all, a pretty bad upgrade experience. I'll think twice about upgrading the next time around if I have to re-set all my preferences - again.
By the way, the default ripping settings of 128kbps VBR are ridiculous. That was bad quality 10 years ago, and today it's just terrible.