Evans E-Ring 14" Clear Snare 1"

Absolutely love this for my snare, definitely prefer it to moongels or tape. It provides the perfect amount of dampening of overtones without muffling the snare too much. Gives you a great clean sound, really easy to mic or record, as well as a less ringy noise in smaller venues. It's also great as a quick fix for terrible-sounding rehearsal space snares.

Apart from the change in sound, you don't notice it's there at all. I've had some problems with moongel flopping around or coming loose, but this ring just sits flat on your head and stays there. I also prefer the clean look of a transparent ring.

I have a cheap snaredrum that has a rather ugly ringing sound. I prefer a fairly dry snare sound, and the Evans E-ring fixes that problem perfectly.
I actually bought both the 1" and the 2" ring, so I can adjust how much dampening I get, which works very well.
It doesn't require any attachment, just drop it on the drum head, the rim of the drum keeps it in place. It takes 2 seconds to put on or to remove it.

Other than that, it is obviously a very simple product, it's plastic, it's solid, so I guess it is a very simple product to make.
But it also costs next to nothing, so I'm very happy with both my E-rings.

Pros
Dampens the drum head evenly. On the snare I prefer the 2" wide version though.
Transparent so you can see the logo on your drum head.
Cons
Bends easily (my children like to take it off and wave it) so it doesn't sit flat any longer. I might attempt to fix the bends by applying something that weighs.
Taking it off (for instance for brushwork) and then putting it back on is inconvenient if there's not much space around.
As I'm growing more conscious about the environment, I would go for natural materials like cloth so wouldn't buy this again. Something handmade by my wife would also have a personal touch to it.