Currently listening to: Chopin Preludes played by Alexandre Tharaud, a French pianist. I'd never heard of him, but I am beginning to think that he is the Josh Groban of classical piano.
Chopin's pieces often sound more technically impossible than actually playing them. Certainly playing quickly with technical precision is difficult, but Chopin helps you out with his finger placements, meaning he doesn't make you stretch you hand in unusual contortions to get from one note to the next (unlike Tchaikovsky sometimes) and often an arpeggio or chord is repeated in every register or in a pattern as your hand moves across the keyboard, helping your muscle memory. What is sometimes more difficult is finding the right expressiveness that Chopin's pieces command in every single note - you can't just bang out the notes one after the next, the music begs for emotion. Tharaud is definitely technically flawless, but I am also enjoying his interpretations.
There are 24 preludes in opus 28, and similar to the WTC, Chopin composed a prelude for every key. Unlike Bach, he did not pair each prelude with a fugue or arrange the pieces on a chromatic scale.