Have used Butler Creeks for ages, they are great. I also use them on my Binos. Glue a small square of sorbothane next to the hinge and they are virtually silent. Also ditch the covers with that stupid little red lever, they're junk, buy the corresponding size objective cover.

With the almost constant rain on the scottish hills, they protect the lens from "Blotting out" right up until you are ready to take the shot. Nothing worse than farting about trying to wipe the lens so you can see the target.