Jeff--
Suction yelpers and diaphragm calls are two completely different animals.
Granted, they are both air operated, with diaphragm calls you blow out, with
suction yelpers you draw air in. Folks can acclimate quickly to either type call.
With yelpers you don't deal at all with the 'gag reflex', as the call remains for the
most part outside of your mouth.
If you're looking to try something new..and give the gobblers something different
to hear, I encourage you to give a yelper a try. I provide an instruction sheet with
my calls, and there are many tutorials available on youtube.