We were a group of 10 (two families) and we enjoyed the Grand Canyon rafting trip very much. There were 18 in total on the raft, which, at times, was a little cramped. We were told the raft held a maximum of 14, however this did not bother us too much as the rest of the passengers were great fun. Our guides, Joe and Scott, were excellent.
Overall, the trip was amazing. My only critique was that we should have been told to bring beer or wine if we wanted a drink when we camped for the evening. Before we flew to the states we had so much to think of for the kit list that beer did not cross our minds. This should have been made more explicit.
Thanks for a wonderful time!