I was at the expo last year. During the contest, I could tell real quick who was using a diaphram and a hand call. and was kinda threw for a loop on the one using his natural voice.
I am by no means good at calling coyotes, but with my untrained ear, I thought the diaphrams won hands down. Not saying the hand calling didnt sound good because it did. The natural voice was really cool and really good but in my opinon was 2nd best.
Here is my opinion. Even I could tell, without looking or knowing who was calling, which was a hand call or a diphram. If the callers were placed to where no one could see them and just hear them, it was pretty easy to differintiate between the 2. So, being the judges are way better at this than me, I would say that if there was a grudge, you would know which was which and could be partial in the equation if they wanted to. By no means am I saying it was rigged, but the guys who think they got screwed knows that everyone knows when they are calling and when they are not, just by the sound of the call.
In my experience, I myself sound better with the diaphram. I can use an open reed good as well, but when it comes to making certain sounds, I always use the diapram.