I can tell you this. We had two wonderfull cruises on the Summit. One was a ten day and the other an eleven day cruise. My DW and I sailed with two other couples and we had loads of fun. The food was excellent the service was the best and the weather cooperated 100%. We loved the entertainment and felt at home on the summit because we all had sailed on the Infinity the year before.
Carnival Liberty New Year's Eve 2007
Liberty of the Seas 5/2008+11/2009
Allure 1/16/ 2011
Independence of the Seas 12/29/2013 Top-notch!