This is the etude that I ripped off for my 'Counterfeiting Blumenfeld' blog post, and I say that proudly. On top of being a revered conductor in his day, Felix Blumenfeld is recognized as Vladimir Horowitz' piano teacher also. I sometimes wonder if Horowitz knew any of his etudes, which I consider very beautifully written but can be very daunting. When trying to adapt the opening arpeggios for guitar, I had been practicing them on the piano as well. You definitely need quite the finger span to get these to sing at the required tempo, but as with most of Blumenfeld's etudes, the beauty is worth the duty! If only I had a bit more pianistic talent.
I highly recommend the channel under the username 'Hexameron', which is named after the collaborative variation set initially written in 1837 by Franz Liszt and thickened up with the help of Frederic Chopin, Sigismund Thalberg, Carl Czerny, Henri Herz and Johann Peter Pixis. The channel is filled with great piano compositions and encompasses many different styles and eras; most notably the era of the Russian musical repression (1900-1929). I urge you all to peruse that great channel!