I've never seen them on a Marlin, but they are well thought of by people who have them. I recently replaced the factory rings that came on my Tikka with Deadnutz mounts. I will not get to the range for a few days, but was impressed with the quality and ease of installation.
The only thing that would keep me from recommending them on a Marlin is the fact that they cannot be easily removed to use the irons. I have always used Weavers on leverguns because they can easily be removed in the field if needed. On a gun with no irons it does not matter.
