Medtner is an often overlooked composer from the early 20th century; even in his own time he was largely overshadowed by the relative fame and fortune of his friend and compatriot, Rachmaninov. His spirituality was an integral part of his life, which is reflected in his music and in the modest and traditional lifestyle he led.
Medtner had an amazing sense of form and melody, and as such there is a great intellectual depth to the music which may render it slightly overwhelming at first. If you are new to Medtner, I would suggest starting with his beautiful miniature pieces, such as the Skazki (more commonly, "Fairy tales"). Medtner's music, especially the sonatas, rewards careful listen.
That said, I must say that such great depth of composition requires a first-rate performer. This performance by Mr. Fellegi is a bit lacking in some respects. The last sonata on this disc (Op. 25, no. 2, commonly the "Night Wind sonata") is a monumental work. Many passages presented here, however, are very sloppy, and he loses clarity of phrasing and expression. Mr. Fellegi plays with constant dynamic where there would be an intense and dramatic climax. The sheer beauty of this work is heard much more clearly with Tozer.
The music of Medtner is difficult to fully appreciate without the clarity of expression achieved by the most able pianists. If you do catch a "bug" for Medtner's music, you would be well advised to invest in a complete set of sonatas performed by Hamelin or Tozer.