The official Harmonix Drum Silencers are a sleek looking product with a solid adhesive, - albeit one that will have a lingering smell - but they do not provide the responsiveness I would expect from a first party product. I applied one and tested it, finding that I missed roughly every fifth note. I went ahead and removed it to make sure it came off clean - it did - and applied it again along with the other three just to see if it produced the same results across the board.
Funny thing is this, you actually have to hit harder to make them work - and as I will explain later, even this doesn't fully work - which produces more sound. They do produce a softer noise, but they require more force, but that comes out naturally as you should be getting frustrated with missed notes. The design is ill-conceived. They ride around the outer rim of the drum set. While I have the version with the raised edge, I have heard from some people that theirs is flusher to the pad and for them, this problem may be less noticeable.
If you do have the raised set let me explain the situation: When you apply the pad, you press down to apply it to the rims and then it also sticks to the center of the drum head. Because the material is so thick, it can't physically bend enough to attach to the rims and the furthest edges of the head. This produces a 1 to 2 inch gap where you are only striking the cover and the response isn't recorded. I don't know how they work on the other version with the flush drumheads, but I have heard other issues about those anyway.
Design - 3: I feel the product does silence the drum strikes to an extent; it really makes them quiet since no one will play them with the pads on. I don't think they fully thought out the design or at least didn't make a cross compatible set for both versions of drums. ('Universal', NOT.) Durability - 10: The pads are strong, thick enough to do their job (where they can be properly attached) and the adhesive is clean when removing the pads and strong enough that they can be replaced.
The pads also give a nice look to the drum set as the rest of the working end is already black.
Final Verdict: Do not purchase this product online, if you would like to try them for yourself, get it local so you don't lose shipping if you need to return them. I would suggest making your own from fabrics and such, but this may void warranties with Harmonix. If you have already purchased them and agree with me, take them back to the local stores for an easier refund. Remember the packing slip on the outside of the box.