11.22.63 - book or show first?

My friend and I are going to start reading 11.22.63 together cause we both love King and neither of us have read it, but I've seen the show about half a dozen times. He asked if he should watch or read it first, but I'm not sure. Instinct says it'd be cool to get his insight reading it without knowing what's gonna happen, what do y'all think?