Medtner is the greatest artist nobody's ever heard of 
Many people seem to just decide that they hate Medtner without having actually made any effort whatsoever to understand his work.
He was an absolute genius. He understood the piano as well as Rachmaninov..... but instead of going for the 'big tune' he goes for Beethovenian architectural quality. As a result, his music is dense and not easily understood.
People resent this, in my experience. They ask me 'why can't Medtner be easier to listen to?'
I did some reseach as I had to write a programme note for this exam. I think the main reason why he wasn't so famous because he was in a wrong time at a wrong place. As many people trying to leave the country during russian revolution, he couldnt manage to get out. (I dont know if he was even trying to get out) Rachmaninov for example, went to US and made a big career. After everything cool down, Medtner went to europe... Germany, France... but that time, people there were mad about "new music"... like Stravinsky, Prokofiev or Schönberg, which Medtner was VERY against at... So people said, his music is old-fashion...
I understand that some his music might not be so attractive for the first time of listening. Maybe not so easy to understand like Chopin or some of Rach's stuff. But still,... If u compare his music to. for instance, Scriabin (of course, not early Scriabin's works because it is not his REAL music), Medtner's stuff is much easier to understand ,in my opinion... for example, Black Mass vs Fairy Tales? ... Yet, black mass is more well-known... (I have nothing against black mass tho, I think it is also a great piece of art)
Well, I think some of his stuff ain't that hard to listen, like op.51 no.3 which Horowitz also recorded. It is really one of my favorite tunes that I can always listen, any time anywhere, with or without anyone...
Mannn, guys... check out his music... This guy is a diamond in mud waiting to be discovered.
Even Rachmaninov said once that he is "the greatest composer of our time" ... So if you respect Rachmaninov as a great composer, check out Medtner too...
(PS, just to let u know, I earn 0$ from promoting his music... haha)