I've read in certain sources (I can't remember which) where it's stated that Horowitz's pianistic capabilities could be match those of Liszt's. And I remember reading about someone who had heard both play, and declared that Horowitz's playing equalled that of the Hungarian maestro.
What do you think? Just a thought...
EDIT: As an added note, why wasn't Horowitz fond of playing or recording etudes? He has proven to be tough enough to conquer stuff such as Islamey or Rach 3, and his Carmen Fantasy is ridiculously exciting - why avoid Chopin etudes?