First I will describe what each one is then compare the three.
Mouth call also known as diaphragm calls are typically a small horse shoe Shaped call that can have any where from one to three reeds on it. It is used by putting it in your mouth and applying pressure to the reeds with your tongue against the roof of your mouth and forcing air in-between the two.

Slate calls also known as pot and peg calls these calls are typically round slightly bigger then a hockey puck in diameter, and about half the height. They usually have a wood cup (pot) with holes drilled through the bottom and encased piece of slate. They can sometimes be different materials such as glass or aluminum. They also come with a striker which is used to rub across the slate to create the turkey sounds. The striker is made of wood, but can be made of other materials too.

Box calls are just what they sound like a box with a lid that is hinged to swing left to right. They kind of look like a one sided rolling pin. The turkey sound is produced with friction as the lid rubs on the edge of the box.

Ok so now you know what they are which one should you pick।I will rate each one one, two or three in ten categories and the one with the lowest score will be the best .I will give a brief description of each category.

Box 22 Slate 24 Mouth 12
Learning curve – amount of time it takes to learn how to use the call and difficulty. The box call is very easy to learn just move the lid back and fourth

Amount of sound- total amount of different turkey noise you can make with the call. The mouth call has a wide range of calls that can be made with it.

Volume Variation- range of volume you can make with each call. This one was a toss up between the Slate and the mouth call but I think you can make more variation with your mouth.

Ease of care- amount of maintain and difficulty. Mouth call is virtually matenince free.

Hands free- just as it says. Mouth call is the only one that does not require the use of your hands.

Price- In my experience the mouth call is far less expensive then a box call, but close in price to a low end slate call.

Carry-smallest and easiest to carry in you pack or pocket. The mouth calls by far because you can carry it in your pocket and the other two you need to put in a pack.

Noise other then turkey-Any noise made by the call when transporting. Although any one of these calls can be stored so it won’t make any noise when you get are getting the call out of your pack the mouth call won’t make any noise.

Weather effectiveness-How well will it work in all weather conditions. Now days they make most of the calls so the water won’t affect them, but come on the mouth call is in your mouth how can the weather affect it.

Easily misplaced-how easy is it to lose or misplace. Well by sheer size the box call wins this one the other two don’t even come close.

As you can see I think the mouth call is the best call you can use. If you can get past the difficulty of learning how it works it is well worth it.
Be back soon!
BEN G.