I never heard them before, lovin' that first song. According to Wikipedia, they were a big influence on Ghost, which is not surprising considering the similarities between The Night of the Witch and Ghost's Stand By Him, mainly the drum opening and the chorus.
You should. I feel like if I heard them 10 years ago I probably would have thought they were too poppy, but I think I have matured a bit since then. Their music is beautiful. I think they may be my favorite new metal band.