So it really does what is supposed to do.
The way that dampens the overtones is truly amazing because it doesn't stick on your drum head, and that gives air and room to your drum head, so it can enhance its attack instead of "adding mud" to its sound.
The only con I can find is that it will fit my die-cast snare or tom hoop, but unfortunately I can't seem to be able to fit it on any triple flanged hoop, which is a huge con for me but not a dealbreaker since I primarily use it on a die-cast snare.
The leathers quality is perfect, but that means that at first it will not be that flexible to deal with so positioning it, will be a bit tricky the first few days, since it needs more tweaking to get the magnets to stay in place. After 3 months of using this product all the time on my snare, although the leather became really flexible it still needs tweaking in order to stay flat. If you keep it folded for some hours it will stay in that position, even if you separate the magnets, making it impossible to firmly sit on the drum head without taking out and force fold it the other way. Now to be fair, although it seems like a con, it's not. I bet in time that the leather will completely soften up and will get more flexible like all leather products do.