Musically it is wonderful though, and the rewards are well worth the effort. There are so many details of outstanding beauty in it - the changes of chord and key in the middle section, the relentless drive of the main motif, the juxtaposed seventh chords in the part where the left hand takes over. The ending, with its two chords like a boulder teetering on a clifftop before the precipitous final descent into oblivion, is magnificent piano writing. It is also remarkable in that he ends it with a simple scale - he hardly used any scales, sick of the sound of them I expect, but here it sounds just right.
I sometimes wonder why I bothered to learn some pieces but I don't regret wrestling with this one.