Pixar did a great job making a prequel to one of our favorite movies. They incorporated references to events in the original movie - characters (Abominable Snowman, Roz, Waternoose, etc.), kids are toxic, Mike training Sully, etc. Overall, very endearing and entertaining movie. Pixar somehow manages to raise the bar with each subsequent movie.
Pros well paced, great story, great actors, voice casting, animation