I used to have one on both of my hunting setups. I switched to a QAD ultra rest HD on one of my bows this year and glad I made the switch.
On occasion, while transporting my bow to my stand, the turkey claw hooks would catch on a limb and twist. I learned to mark it with white out so I could replace to the position where it was sighted in. While I liked the overall performance of the rest, the questioning of whether it was in the correct position after a mishap while drawing back on a deer was always in the back of my mind.
I know guys that had the QAD, Ripcord, and NAP Apache and all speak highly of them. It came down to a overall construction and appearance/craftsmanship when I bought the QAD.
If you would like the Muzzy Zero Effect, I still have it. It was for an 05 Mathews Switchback. If you want it, I will send it to you. If you like it and keep it, as a good gesture you can send me a $10-15 gift card to a sporting goods store to cover S&H and the rest. I'm not concerned with the money, was just keeping it if I ever sold my bow.