I liked the depth of petshop more. It delves into the motivations of people and the things that make us human with a lot of room for grey area and interpretation.

Even the way D explains his pets to Leon makes things seem open ended, like the characters themselves don't have all the answers and admit it. They're much more real that way.

I always remember the one scene where D cries for Medusa because he didn't realize she would follow her master. Even D can be surprised and vulnerable sometimes.