Both are brilliant, and sadly... totally ignored.
Richter's recording of the third is so wonderful, and I have a solid recording of the 2nd from Boris Lvov.
Richter said the 3rd is difficult to play, and that one of his teachers made him practically shed tears when he performed it so well, because he felt he could never play it at that level. The 2nd is more about melody and the 3rd is more about rhythm.