Would you be more comfortable surrounded by other gay cruisers? Going with a gay group allows gay travelers the opportunity to "be themselves." (Note that the same issue applies to all cruise goers. If you go on a cruise with primarily American travelers and then go on shore excursions with those same cruisers, you don't have to worry about blending in with the locals. Personally, I'm not sure that is good, but some like more of the comfort of the known versus the excitement of the unknown in traveling.) The issue of comfort and atmosphere is probably the primary reason gay travelers choose an all-gay cruise or a gay tour. Are you looking for new friends or romance? Many GLBT cruisers claim to have developed long term friendships while on an all-gay cruise or gay tour. Opportunities for romance are probably also higher with a gay tour group. Finally, often your traveling companions on a gay cruise will tend to be younger. So, if a "cruise nightmare" for you would be to be surrounded by middle-aged married couples or senior citizens, then you might want to book a gay cruise tour or all-gay cruise.
Alternatively, would you want more diversity? Some gay cruisers want to be surrounded by a potpourri of other travelers. For many of us, gay or straight, vacation is a time to mix with other cultures and life styles. You will also probably have more choices of cruise ships, dates, and price ranges than if you restrict your cruise options to an all-gay trip. The more flexible and open you are in your cruise plans, the more bargains you will find. If price is your number one factor in choosing a cruise, you may have to sacrifice location or time of year if you also want an all gay tour.
There are gay tour companies that put together packages for gay cruisers. Some of these will "take over" the ship for an all gay trip. This is especially true on small ships or sail boats. Other times, especially on the mega-liners with two thousand or more passengers, the gay tour will just be a part of the regular cruise, with parties and socials scheduled for the group. Gay tour companies seek out "gay friendly" cruise ships. Some of these companies have been quite successful and have lots of repeat guests.
Check out the gay cruise resources on page 2.