If you are a Turkey hunter and have used diaohrams, you can't go wrong with one of those. I prefer double and triple reed calls. Hands free and can make any cow/calf sound as well as bugles, chuckles, and grunts. Most realistic and versitile.
BUT! . . . If you gag just thinkin' about a diaphram in your mouth, I have to recommend the Primos Hyper Lip Single with Tone Converter. Mylar reed call that is easy to use, versitile, and WORKS! The Hoochie mama is foolproof as well and is hands free. I guess some guys tape it to their bow to squeeze after the shot which calms the elk down.
BUT . . . If you aren't good at any of them, leave them all in the truck.
They all take practice, practice, practice. And not in camp!
Good hunting . . .