There are many and varried opinions on this subject here and elsewhere. It's a touchy subject as there are many agents here from different types of agencies. The Cruise-Chat rules prohibit solicitation so general responses are all you'll recieve. My advice is simply to shop for someone knowledgable about cruising and the cruise industry. Also someone who you like dealing with and who will answer your questions and ask you questions about your family, ages and lifestyle to get a feel for who you are and what line would best suit your needs.
After calling a speaking to a few you'll know if you're dealing with someone that fits you and your needs or if you have someone interested booking a cruise for their benefit. I'm not sure there is a right answer that fits everyone. With lots of choices and lots of great people in the industry you won't have to search too long to find a good agent. Good luck with your search, I hope you find someone that's right for you.