Best would be a relative term...as it would be readily apparent that most work just fine. For me the easiest I have found to use and have had several new hunters work with ease, is the Lynch model 101 fool proof turkey call. Pretty good name and it pretty much works that way if you ask me. Just chalk it up and pull the paddle and your good to go. I have tried numerous other models and some are a bit tricky, this one however will get you going and make you sound good from the get go.
You shouldn't limit yourself to just a box call...another user friendly call is the Ole Yeller slaytek. Easy to use and sounds great.
Get yourself a mouth call..single cut diaphragm and practice with it until you can get the yelp down...you might need to have someone give you some tips as to holding it in your mouth properly and making the sounds? You tube might also be of some help. You will find you "need" to use a mouth call when things get busy(shaky as in gobbler fever) you don't want your hands fumbling with anything other than your gun!
Charter member of the "I only shoot bar belly geese club". I'm a Bar belly goose purist!