His etudes are interesting, but I think playing Chopin's or Liszt's etudes would fill the repertoire better. If you have previous experience with these, why not play some of Debussy's etudes...

I believe that these etudes serve different purposes than the Chopin or Liszt etudes, though. I think he really explored the lesser studied aspects of technique, and put them down. For example, his "Pour les Agrements" is unique. The first book deals with your common technical problems, but I think the second book is truly one of a kind.
I have sightread some of these. They can be really hard. I like the Octave Etude, particularly...
I think that they are worth the effort- These are probably some of the least played etudes, from the great composers.
Mario Barbosa