The diaphragm has become my go to call. I have been very succesful with them.
I did buy an Albert Paul custom box this summer and will definitely trying to call some up with that bad boy this spring tho!
I've not had much success with a slate/pot type call although I attended a seminar where Walter Parrott said they sounded more like a turkey than any other type call.
If that's so, why aren't they used in the big calling contests???