I agree with Pete, at least for running events. With a single point turn around, there may be less potential for inaccurate cone placement on race day. Of course, runners may run bit longer, but not less, assuming the single point is properly set up.
Bob's experience with the half marathon turn around is one of many such incidents that inform me that simpler is better, especially when you are not familiar with or confident in the course layout team.
I remember watching Greg Meyer at the Cherry Blossom race in 1983. Going around a single point turn around, He slipped on the damp pavement and fell . I suspect this turn around did not bother him too much despite hitting the ground hard enough to open a bloody gash on his leg. He got up on his feet and set the world record for 10 miles.