They do help amplify and hear - but at some point, just like with any amplification, they can be too much.
Though primarily looking for protetion over amplification, I started using the H Leight Sport Impact Bolts a number of seasons ago [after starting with the foam plugs]. First while duck hunting to hear the calls better [than with foam plugs], then predator hunting for the same reason [calling] and now also in the big game woods and upland fields. I like that my ears no longer ring after shooting like they use to.
I try and adjust the sound level to just about what my normal hearing level is. However, it is easy to turn up the volume if I want to hear something better - and I have done this effectively [waterfowling to hear other guys across the lake; also, to better hear approaching crunching sounds in the BG woods]. I find that I can concentrate on my shotgunning better without reacting to the shots as much since I don't 'hear' them.
I think they are a very good option for the price and work phenomenally. Battery life is good but obviously impacted by colder temps. I find them acceptably comfortable and they do not interfere with the gun. I find they work well for direction overall; there have been some specific instances where direction was tough to immediately discern [but I think it would have been regardless].
I cannot compare them to Walkers, others or even other H Leights muffs as this is the only pair I have used [bought them since they are the only pair I found that published reaction time, NRR and other performance specifics].
I do believe I will probably shell out the $$$'s for an ITC pair down the road when these wear out but these have been a great intermediate step.
That said - Drawbacks:
Blowing hard highball/goose calls will shut them down [they cut to 82db so there is still sound].
Wind OCCASIONALLY causes issues; it is a combination of direction and wind speed thing.
They are hot when hiking or early season birding; conversely, late season and waterfowling, they keep the ears toasty [when hiking especially in non-birdy areas or when humping back to the truck - I move them off my ears].
I recommend them as much as I can to others - regardless of whether you are loking for amplification or protection. I actually recommend anything as being better than nothing. Ear buzzing, ringing and saying 'huh?' the rest of my life will not be fun - protect what you have.