I personally find Camp Snoopys to be more relaxed in that they have more lush landscaping, soft earth tone colors, and softer melodic music.
Planet Snoopys have extremely bright colors, uncoventional patterns and archetecture, less emphasis on landscaping (and shade), and loud fast paced music. To me, all of these things add up and eventually become physcially draining. I could stay in CP's Camp Snoopy much longer than Planet Snoopy.