I hadn't used that brand of electronic caller, however I have downloaded call sequences and used a mp3 player and a old set of computer speakers (they run off of batteries) and used it very successfully varmint hunting here in New Brunswick. So I would say that any electronic caller could definitely improve your chances given it's used strategically.
My primary clips have been a howler, coyote talking, and of course distress of rabbits that start with "chops" to a "howling - please help" call. I generally start with coyote talking clips and see if I get any feedback. I wait 10 mins +/- then proceed with distress rabbit, wait a min or so between usually give the distressed rabbit howl once every 5 of the distress chopping. In my experience I can bring coyotes in the area out for a meal about every 15 calls - or 15 to 20 mins. Given I'm giving a break of approx a min between the calls.
In my experience I wanted to note that I find coyote calls themselves simply affirm that they are in the area. Continuance of calling coyote calls (even distress calls) make them evade the area. I feel the route to getting coyotes to expose themselves so that you can take the shot is motivating them to come get an easy meal.
Varmint hunting is some of the most challenging hunts one can engage in. I've had the pleasure of trying pretty much every type of hunting in all sort of parts of North America. Varmint hunting has a challenge similar to other hunts especially when you can coax them in with a bit of "phone ###" LOL. Good luck Good hunting.
Jake