Pros: really good suspense in the beginning, some really surprising moments, and skillful acting from Elizabeth Moss.
Cons: The suspense of "where could he be?" gets a little old about halfway through but continues to be a prominent feature of the film. The bad guy's motivations are really weak, I didn't find it convincing at all. About 2/3 of the way through I realized that we were just expected to accept that the bad guy is evil because, well, he just is I guess. And there were some glaring logical gaps (as can often be the case with horror/suspense) that I really had to work hard to ignore. Didn't really feel the ending because of the aforementioned cons.