This rating is for the Nov 2016 release. The prior release is 5 stars.

I don't like the new version because:
1. Mutliple hotmail accounts are broken. They take one to the Microsoft log in page. Pain. (Checked both in Chrome and in Firefox). I have two. So, one is greyed out and the other is displayed in red. The one I used last (through manual log in) gets greyed out and the other becomes red. Still, logging in is required for both.

2. The right click was removed with all its nice behavior. The new look is clunky and requires getting used to it.

Version 3 rocks. Version 4 is... ehhh... unusable.

Had to downgrade to version 3 to get 5 star performance.

If usability is restored, I will change the rating.

For my environment, it is not about Firefox since version 3 works fine in the latest Firefox.