If you are talking about the electronic calls, I really like mine. Mine is an older one they no longer offer, but the “Hammerjack” is basically the same as mine but with the newer / better controller. The one I have did not originally come with the “fox jack” (the wiggly thing on the side), so I bought that separately. It works well without the fox jack, combined with the fox jack it works amazingly, the call unleashes the sounds while the fox jack really grabs their attention, takes the focus off of you. I have used it in below -20 with just regular rechargeable batteries and have done up to 6 stands (a fair amount of call time) and have yet to have the batteries be an issue, but always carry a spare fully charged set.
If you’re talking about the mouth calls, I have no experience with them.