Harem fantasies are one of my more popular packages, and I think anybody who has ever done one love the experience! Just make sure that the 3 ladies know one another and that each has worked and enjoyed working with each of the others previously.
As long as the ladies are genuinely friends and playmates, and not just randomly put together by either yourself or the agency, you should have a fabulous time. Conversation should flow, and the dynamic will be amazing!
Have fun ;-)