Look, if you need some rings for your toms for cheap and you're good at maintaining your equipment, then go ahead and snag yourself a set of these. If you're like me and you have a hard time paying for things that you could make yourself from some old tom heads an Xacto knife, these are a good compromise.
I have to say, my first 14" ring that I put on my kit was bent out of shape and buzzy after one rogue hit on my floor tom. The 10" and 12" rings do their job pretty well, but they still don't really like to "grab" onto the head like some other rings do.
So to sum it up, my opinion is this: It's a reasonable, cheap solution for some quick tom muffling. But... if you're serious about your sound and you don't want to have to worry about buzzing from the rings, then just spend the extra $5 for some E-rings. There's simply no comparison.