I' ve had bow mufflers on my last two mathews bows and I love them! They do help quiet the bow even more by covering up the limb pockets. A lot of noise comes from limb pockets!! They look great IMO and are very univeral (they can be trimmed to fit your bow). They help quiet your bow while on stand (you can lay your bow across an arm rest and not worry about noise. They protect your limbs from nicks, scratches, etc. They also absorb scents great. I take many scent precaution measures. One of them is storing my bow with Scent wafers and the bow muffler soaks it up and disperses the scent for days. I also soak them down real good before each hunt with scent killer.

I have not seen any adverse affects on speed, what-so-ever.

They are right up there in my top 5-10 bow mod' s.