My opinion is each call maker has there own "signature" sound. To me it's the way they interpret a Yelp a cluck a purr....and the way it sounds to them I'm sure everyone's ear can pick up different frequencies of each call and it in turn ends up being tuned into their calls. There is no doubt that all of the call builders calls will kill turkeys, find one that really tickles your ear hairs and go with it, having confidence in your call and calling abilities goes a long ways.
Eric