The new iWork apps look beautiful. The new icon for iPhoto and the app itself are very attractive (but what's wrong with the animation when entering fullscreen?). Usage of pastel gradients is much more tasteful and subdued. Same for Safari 7 - it looks brilliant! In general, everything feels much more coherent than iOS 7, and many changes definitely feel like improvements. I was worried for OS X's future direction but I gotta give it the OS X team - they really picked up the pace lately and I'm very impressed.