I use a box call. I have two large ones and a small one. I carry one of the large and the small. I hunt a relatively small area and I don't want the toms to hear the same call over and over.
I also have a tiny box call that mounts on the barrel of my turkey gun. It has a string that I can pull with my left hand in order to get the tom to gobble and stick his neck out for the last time.
I've tried mouth calls and you can get great sounds out of them, but no matter what I try, I end up drooling like a St. Bernard every time I use them. So it's use a box call or drown.