Pirates was not the best of the series, the largest disappointment being the direction they took Jack Sparrow, but it did deal with a plot line that had bothered me in the previous movies. Maybe it was because of all the negative reviews, but despite its faults, I had fun watching the film (much like the fifth Transformers movie that I saw earlier this week). I'm pretty certain that they will make another in the near future.
Baby Driver was amazingly well filmed with a story and characters that hooked me all the way through. As over-the-top the entire movie was, it also felt real and believable. The twists and turns to the story felt like natural extensions of the characters and their journeys. It certainly earned it R rating, but not in a tasteless fashion. However, it is the soundtrack and how interwoven the music is with the movie that truly makes this movie a must see.
Overall, I would recommend seeing both films.