Unless you're not interested in shows, I'd say MGM would take longer. Really though, it depends on your interets and what you are or are not willing to see. If you want to see it all, you'll be there a whole day. If you skip a specific type of attraction (thrills, shows, kid-oriented rides), then you will most likely not be there the whole day. Personally, on my last trip to AK, I did Kilimanjaro Safaris, Pangani and Maharajah trails, Tarzan Rocks, It's Tough to be a Bug, and the parade and left by 5pm taking things at a fairly steady pace. I didn't even see any of the rides in Dinoland, anything in Camp Minnie-Mickey, Kali River Rapids, or Rafiki's Planet Watch.