Of the one listed the Spitfire is the hands down winner. The JS PM-4 is pretty nice also. My hunting partner runs a Spitfire and we've killed a few dogs over it. My B in L in WI does control work for the local farmers with a Spitfire. I hunted with a quide down in NM insome horrible conditions , high winds and blowing dust, most of the time he mouth called but broke out a Spitfire when he had to push sound continously at a couple of stands. The stock sounds have worked well. 90 percent of the time I use the same four sounds and called coyotes in MT, WA, AZ and NM this year. Your stand location, use of the wind, and lack motion on the stand will have more to do with calling in coyotes than the sound you use.
I started calling nearly 50 yrs ago and have used portable phonographs with 45 rpm (you younger guys might have to look in a museum to see one), cassette players , CD's, digital, even built my own remote caller with a camcorder remote sound system. I prefer the Minaska remote because I can run the caller without reading glasses on the stand. They all have called coyotes, even the cheapest mouth rubber band mouth calls have called preds for me. The newer light weight remote callers just make things easier.
