Talk about obscure! He's a hard composer to get to know. If you don't want the entire opera Doktor Faust, two sections (Sarabande and Cortege) have been extracted by the composer for concert use. There used to be a fine EMI recording, but I don't know if it's available any more. On CPO, there's an interesting disk of orchestra music which is well worth the investment. Very colorful and entertaining. If you're into chamber music, string quartets 1 & 2 are also on CPO and very enjoyable. A previously mentioned Piano Concerto is a must. I love music of this period, but Busoni is still hard to come by, and even then an acquired taste. Still, if you like it, try Enesco, too.