I never ever read or watch reviews before I read a book because I am a serious hater of spoilers. I'm majorly sensitive to them as well. Like something other people would be fine with and not see as a spoiler would be a serious problem for me.
I often watch or read reviews after I've read a book because that way I can't be spoiled and I love hearing about what other people thought about that book. It gives me a new perspective and ideas about the book, sometimes reviews make me change my mind about a book because I didn't see them in that light until the review.
I sometimes watch reviews of really hyped books that I don't want to read and end up thinking "Oooo, I wanna read that now!" ...and so the TBR pile grows!
Talking about reviews, I recently participated in the Write On ReviewAThon. You can read my post
here and check out all of my reviews
here!