CS Lewis had definite sadistic tendencies evident in That Hideous Strength and the lesbian protagonist within. He was a bit too much of a moralist for my tastes. He turned atheist after reading Lucretius, and he came back to Christianity in a very literal and cold way, I think.
Tolkien is the superior writer of the pair, because he reached into the deepest mythologies available and was a more comprehensive world builder. As a Catholic, he was as sumptuous as Lewis was austere.