Mary I think that what has evolved from your question is not primarily what type of "system" sailors prefer to sail under but that first and foremost they just want to sail, and to expand their enjoyment of the sailing experience, they like competing/sailing against other boats/sailors!
What ever the "system" that their competitive sailing is conducted under is really secondary and "when push comes to shove" they will sail under whatever rules/conditions/circumstances apply at the time.
I know that this doesn't directly address the wording of your original query, but personally, I am not sure if there can be a truly "objective" response to it, the responses that have mostly appeared are all in the main, highly "subjective" and as such I am not sure if they will ever accurately give you a definitive answer.