I really enjoy turkey calls, and pretty much use three different types of calls.
Box calls are loud and realistic, and easy to use, as well as fun to play with... As you start to mix in clucks and yelps, they become a bit more challenging, but are still the easiest to use in my opinion... And when I want a loud call, it is generally a box.
I probably use mouth calls the most to finish birds... Realistic sound, and no movement. Also extremely versatile. I often walk & talk when moving to a bird (make soft clucks and yelps as I cover ground). So very often the last sound a bird I have killed hears is the cluck of my mouth call... Interestingly, I do not get as much entertainment out of running a mouth call as I do friction calls though... I suppose it is less like a toy in my mind's eye.
Scratch boxes are a bit more challenging than a box call, but they sure make the low-end sweet nothing's... Those quiet clucks and purrs and low contented yelps... And, you can still get reasonably loud with them (although not like a box call). It has a different and unique sound as compared to other calls, and can be a real advantage in the woods... Maybe cause they are new to me, I tend to enjoy playing them more than my other calls currently.
I never really got into pot calls... Maybe if I got a hold of a good one, my opinion would change.
What calls do you all like, for what, and why?
