I like it, but regardless of one's aesthetic opinions I think an important thing people are missing is the move towards UI elements being overlays on top of content instead of sandwiching or interleaving with content. This is very apparent on some apps like iOS Safari, Maps, etc. The general idea is your app content is a full screen/window canvas and your UI sits on top of it, which allows it to get out of the way of the content. I actually really like this move. The transparency serves a purpose here, it helps retain that full size appearance even when UI elements are visible. The glass effects essentially serve as a way to generate some contrast while still making the underlying content visible. Even with large UI elements on screen like sidebars, you still get the feeling that the content is prominent. I think this is going to influence how I build my own web ui's moving forward.