I've been reading the comments here and feel I need to add my own thoughts. I have been an Evernote user since 2012 and I view the recent UI changes positively. For me, the interface has become more readable. It seems to me that regardless of the UI changes, the stability and speed of EV are continuously improving as well. Since this thread mostly contains negative reviews, I thought I would also share my opinion. Personally, I would not want the UI to revert back to what it was before version in 10.
