Lang Lang is a very controversial figure in the classical music world. I think he's more interested in showing off like a magician visually, as opposed to musically. One of my teachers calls him Bang Bang which I think isn't very nice but banging the piano is considered by many musicians to be the worst crime. He did this in Liszt's second Hungarian rhapsody. The Chopin waltz in A flat major is a very lyrical piece. A work of art about farewell. And it should be played beautifully rather than rhythmically because playing this piece rhythmically just isn't the right style of the piece and it requires no effort at all. Showing off visually just isn't art related. We are more interested in musical depth, poetic depth, how beautifully you can play passages that are meant to be played beautifully, how much excitement you can create in passages meant to be played with lots of excitement, et cetera. I think he has great techniques but he chooses not to play well because I think he considers money more important than playing well. I think he's pursued money and show business and this has resulted in his playing not being as good musically as it was when he was much younger. In contrast, Yuja Wang doesn't seem to find anything difficult and therefore is able to focus more on her musicianship. She's a much better interpreter.