I looked at all 3 before choosing Tetra. I already have a hearing loss and needed a device that would compensate for my loss to be able to hear my squadmates, voices, etc., and still protect what hearing I have left when the gun fired. Tetra was founded by 2 audiologists, so hopefully they know what they are selling. With Tetra, you can take their online hearing test or better yet send in your recent hearing test results and they will tailor the devices for your hearing loss. Harris & Sons also offers this service, but at over 2X the price of the Tetras. Harris & Sons does include Bluetooth, but that was not worth the extra $$$ for me. Not sure if ESP offers a customized option?
I just put in my order for the Tetras and haven't gotten them yet, so I cannot comment on their actual performance. I have tried Walkers, Peltor, Axil, Etymotic Gunshot Pros, and Otto Noizebarriers. The Ottos were BY FAR the best of the rest, but even with their amplified setting they could not compensate for my hearing loss. If you have reasonable hearing, I would HIGHLY recommend the Otto Noizebarriers. They are very comfortable, last all day, have one of the highest NRR ratings, and are super easy to use. Also very reasonably priced for what you get if you can live without the Bluetooth.