I love 99designs - working in a creative industry myself, I know how hard it is to find good designers. Well, 99designs has thousands! The best thing I can say is that the designers here visualise what's in my head even better than I imagine it! And we have a lot of fun along the way!
Many people on here have been so courteous that I really hope to work with a wide number of the designers in future. And as with most things, you definitely get out of it what you put into it.