Often we will talk to friends but many, if not most, will turn to the Internet. After all, "if it's on the Internet it has to be true." Cruisers will turn to a website like Cruise Critic where they will find reports on the various ships and destinations and most importantly reports of the experiences people like them have had on a particular cruise. Others might turn to Trip Advisor where folks (myself included) make regular reports about our experiences at destinations, resorts, hotels, restaurants etc.
Now, having said that I want to make a few suggestions on how you should use these tools that the Internet has placed at your disposal.
Another thing to consider is whether all the reviews are critical or they are positive. No vacation product has ever pleased all the people all the time. So I suggest simply disregarding or skipping over those. I'd also look askance at any set of reviews that sound too much alike.