Jennifer,
Without knowing the ages of any children in your party (if any), it is a bit hard to say. Here are my general recommendations;
Groups with smaller children:
Typhoon Lagoon, because of the beach area and wave pool
Groups with pre-teens:
Blizzard Beach, because of Tike's Peak
Groups with teens: Blizzard Beach, because there are more 'thrill' rides.
Adult-only Groups: Tie. If you want thrills, Blizzard Beach. If you want relaxing, Typhoon Lagoon, for the Shark Reef and beach areas.
I hope that helps. If you want to give me more info about your group to help decide, just send me a question from my bio page.
Have a magical vacation!