I haven't used this particular one but just know going in that this will not replace a conventional sharpener. these things are good for when you can't get to a shop and you need to extend your edge life but don't be thinking that you can buy one of these and never see the inside of your local pro shop again.
It isn't meant to replace proper sharpening. It falls somewhere in between sharpening and using a ceramic Y-stick/honing stone.
Sharpening works by removing metal in the shape (radius and hollow) the sharpening chooses. Y-sticks work by "bending" metal of the edges that have "curled" over to the outside edge of the blade back to "straight". Stones remove this "curled" metal.
The Edge again uses a flexible piece of metal with diamond grit which flexes to the contour of the hollow and to some degree the radius to remove metal from inside and outside the edge. Though nowhere near the degree or accuracy of an actual sharpening.
You can in my experience use it over quite a long time. Though you have to be one of those people who don't prefer super sharp blades.
I do like the idea of this to use in a pinch. Many of the rinks around me have exposed concrete between the rubber matting on the bench and sometimes you hear the horrible crunch sound.
Does the Edge Again work on different hollows though? Or do you need to purchase different tusks for each hollow?
I said radius in my other post when I meant hollow. Will edit.
There are three different tusks I believe. Regular skate, goalie and figure.
The regular skate one will work with different hollows as the tusk flexes. Though I imagine it works better with some hollows vs others.
It won't repair serious damage but it will repair minor damage better than a Y-stick.
Y-sticks/stones are good in a pinch. This you can use in more than a pinch.
For example if you can't get to a sharpener for a week or two (maybe even longer) it works perfectly fine.