I use this on my old Tama Swingstar 22" bass drum. I bought this because I felt the drum had too much of a "pillowy" sound, and this certainly fixed that.
It really does what it's supposed to, and adds a lot off attack. For practice I prefer to use felt beaters on it, because the click you get from it can be a bit overpowering. For recording, I've had good results using plastic beaters, as it's easier to control how much attack you hear by mic placement.
Be warned though, it really does add a HUGE amount off click/attack, so if you want something more subtle, look elsewhere. Good for extreme metal.
+ Impossible to break
+ Easy to install
+ Adds an enormous amount of click
- Adds an enormous amount of click. It can be too much!