Weeks ago, i had the chance to see Mr Hamelin performing the piano concerto in B flat by Brahms. (Perhaps the hardest piano concerto)
I never saw such a solid pianist

. He posses an amazing control of the instrument and his technique is perfect. He got so much applause that he played an encore, i was expecting to listen to a virtuoso piece by Alkan or Godowsky but instead of that, he played a lovely and simple french song.
After the concert we cordially chatted about his future plans and his current reportoire. He told me that he will record the 24 etudes by Chopin and the momumental piano concerto by Max Reger with a german orchestra. He told me that so far the most difficult piece he has ever played is Reger´s variations and fugue on a theme by Bach. He also told me that he had several problems learning and playing the Hammerklavier by Beethoven.
He doesnt like that most of people recognize him due to his recordings of the hardest piano works ever written. He wishes people realize that he is more than technique.
He says the most difficult piano piece ever written is a set of etudes by a french composer (i dont remember his name) who was a comtemporany of Alkan and Chopin.
Hope you find this information useful.