Haven't used those but did have a similar pair of custom-fit ones from a different maker.
I found that they were great at the range and had some limited usefulness in the field.
They were good if you were stationary and listening for any movement or maybe in a duck blind with someone else. If you are moving thru any dried leaves or brush they amplified your own local noise to a distracting level if turned up loud enough to detect little brown birds trying to sneak away.
FWIW, Your mileage may vary.
