I went to a shop Tuesday that had a whole gob of calls by different manufacturers. The people that work there actually turkey hunt and do pretty doggone good at it. So I asked them, of all the box calls they have on the shelf (they had some custom ones for over $100 each, all the way down to the normal ones you find at Walmart) which one did they USE.
The guy grinned at me. Walked right past all the high dollar ones. Picked up a call I wouldn't have even looked at twice. It's a Quaker Boy "Curve". He opened the package of it, and hit it a few licks...and handed it to me. I gave it a shot and nodded my head and said "that'll work". It's a longer call than what the rest of them are...but it sure sounds good...and price was around $25. There's like 4 guys that work there that turkey hunt and all of them said they had 1 box call in their vest...and that was the one they have in it. They carried all the major brands, a few local custom makes, and that was the one they sold me on.