I have a few of them both green and the older leather top. They work just fine. Some need a little work to quiet them. Many times the rubber grippers will be either hard or stretched out from having arrows stored in them to the point where smaller diameter arrows will slide out. You can buy replacement grippers for the four arrow model but I don't know of anyone that makes then for the 8-arrow.
If you get one make sure you get the right length for your bow. They were available in short and long for different length bows. Some bows, I believe your KMag is one, have inserts on the riser and you could use a quiver that has an upper spring arm and connects to the riser insert on the bottom.