Blimey: I listened to his 2 piano concertos for the first time a couple of days ago. The 2nd is a preposterous piece isn't it ? I had a much better time with the 1st which focuses on late Busoni works.
Haven't listened to the orchestral version (as opposed to the piano transcription) of the first yet. After reading your post, I put the second on in the background. It finished a few minutes ago. I wasn't paying too much attention (I don't think I would have lasted otherwise). At least I can say I've heard it now :/
