While I enjoyed Shadow of Night I liked A Discovery of Witches a bit more. One thing that I really enjoyed was that I learned a few things (like where the term "bedlam" came from) which is always awesome. Another thing that always interests me in Time Travel books is how visiting the past affects the future. I really liked the choices that Harkness made in that regard and I especially can't wait to see what the implications are in the present. 
 There are A LOT of characters in Shadow of Night and quite a few of them are different from A Discovery of Witches which can sometimes be confusing, but I enjoyed getting a glimpse of Matthews past while he was their with Diana.