I am with EFH on this one too. I have not failed to have a turkey gobble at my Palmer Hoot Tube, but maybe 3-4 times in 8 years of hunting. It is a great call when looking for a roosted bird or hunting an area you don't know. I hunted out in KS last spring and had a barred owl 35 yards from me and when I called he about blew our ears off. I called back and the tom at 75 yards about blew our ears off! I think it is just a matter of when and where you use them.
Locator calls allow you to move and set on a bird without using a turkey call! If a bird answers a call and your not setup right, you can't just close ground, how do you know he's not on his way. Now I agree, when their on the roost they usually tell on theirself, but later in the morning they allow you to get inside that comfort zone without him looking for you. Locator calls can be a very valuable tool in your arsenal!