That's a pretty general question. I think it depends on where you live, where you hunt, the amount of pressure the coyotes receive, the calling devices others in your area are using, etc. If you are hunting in an area that is popular to other coyote hunters, chances are that the coyotes are educated and wont respond to a call. If everyone in your area uses an electronic caller then I would use a mouth call to gain the coyotes attention. I have found, the pups are uneducated and will come in at least once to any given call out of curiosity. If you blow the chance to take it you will have to step it up a notch and "feed" him. They might respond to one call one day and a different call the next. Say a guy before you calls a coyote in on a cottontail distress, takes a shot and misses, the coyote is less likely to come back in to that call. You will have to play with many different calls and see what works.

Here is central washington I have found a fawn bleat and challenge howl work the best. I'll throw a bark or mouse squeak in to get the dog to stop so I can deliver a well placed shot.