In all the years I have called coyotes, I have had the opportunity to use both styles.
For me, I strongly prefer a mouth call over the electronic callers. With the mouth calls, I am better able to change sound tones, cadence, and rhythm. There are also countless mouth calls on the market. I really prefer the open reed calls as they are so much more versatile than the closed reeds. If you really want to practice calling coyotes with a mouth call, take a few days and head to Wyoming/Colorado/Dakotas where the population is higher and calling is a little easier than this area. I always had more satisfaction from calling them in by mouth than any other way.
The ecallers have their place I am sure. The problem I have had with them, is they sound like exactly what they are, a machine. The same sound plays over and over on a loop. Talk about educating a coyote in a hurry. I feel they work excellent in areas where there is very little calling pressure and you are dealing with fresh coyotes. But in hard hunted areas, I do not beleive they are as effective as a mouth call.
This is coming from calling coyotes in the Western Plains states as well as the wooded and swamp areas of the Upper Midwest.
So, what is your opinion between the two?