6mm is the literal worst for medium and big game, but that's another thread. It was awesome. They may still be going on that one. I haven't checked.
All of the other calls, except maybe a Squealin' Hen, are better. That's what worst means. If something is the worst, then everything else is better.
I will say one thing for a box call. I never felt like I almost got knocked out by one. I killed a gobbler yesterday. It wasn't paying any heed to anything but a trumpet. I tried a pot call, but the bird was across a property line from public and probably heard a lot of those from people trying to call it out of there. Not so the trumpet! I keep my trumpets tethered to the call organizer I keep on my chest.
Anyhow, the gobbler collapsed at the shot. (.410 T9.5s at about thirty yards) I walked up to retrieve my prize. It hadn't so much as twitched until I touched it. They it came alive; not really, but you get the idea. At some point in the ensuing tumult a trumpet fell out of the pouch. The gobbler's wing found it. WHOP! I was stunned for a moment trying to realize what happened. The wing slung it around by the tether and put it upside my head like a nun chuck.
When I returned home and told my wife the tale, she told me I should keep the call in a display case and hunt with something else. The response to asking why was something like, "Do you have any idea what I paid for that thing? It's mammoth ivory. Put it in the display case and hunt with something else!"
The case has a lot of custom box calls in it. I just don't hunt with them anymore, because they're the worst.