In my opinion...the call is only as good as the caller. I typically use a true double or true triple...I have only found these made by Primos. In the end a simple single reed, if used right, is as good as anything else.

You'll have some disagree. They will say that birds are used to hearing this call or that call. I don't believe that. I don't believe that birds get "call-shy". I think that is generally an excuse for our ineptitude or the reason we make up in our heads when the bird doesn't roll right in like we want. I've hunted birds that I KNOW have not been hunted and seen them do exactly what public land birds do and vice-versa.

My answer would get the call that you think would be most comfortable. I often have to get smaller framed calls for my mouth.

If you are just starting out using a mouth call, then it is varied as to what mouth call will work best for you. If you are experienced with mouth call use, then I would just say that I prefer the Primos Tru Double. Each of the two reeds in this call have their own frame, so they don't stick together. I like the sound, too. It's a mouthful, to the uninitiated, though. Frankly, there are a lot of good mouth calls out there, and it is purely a personal preference.

ditto on the true double recommendations. I've had good luck with QB screaming green.

Find a brand that fits your mouth and go with that. I bought a Preston Pittman call once, and it is too wide to fit comfortably in my mouth.

True, that. It's a mistake to buy one mouth call, try it and fail, and give up without trying another. Unfortunately, these things do cost money.