Atleast Rin actually loved her and cared about how Miku feels and asks her if this and that is okay to do before, after and during she does things to her. Len loves Miku but not caring about how she feels on what he does to her and letting his feelings take over him when things don't go the way he wants it proves that he doesn't deserve her and is a piece of shit. Rin isn't actually the sanest choice but she as much deserves her more.
