We cut tops mainly, have to limb as we go, the marker might be fine in bare trunks but I cannot envision using it on tops, it's just easier for us to eyeball it, don't have to set a saw down, keep track of the marker in debris. When we do get cull logs, sure it would be an effective speedy method. But I think after doing it this way for thirty five years, I'd prolly be slower learning a different way. The only real down time we have is filling saws with mix and car oil and when we stop to load. It's really not that tough to eyeball after you've done it awhile. Each to their own, I'm not going to pay help to sit down a saw and try to mark tops, they can have several cuts made during that time. After each top is cut up and loaded we just push all the small cut off limbs up with a 4wd tractor and loader and drag another top up and repeat process. That way we keep the land owner happy by piling and burning all the left over brush. If you use a mingo on tops how do you run it down all the two and three inch limbs that get cut up that still have leaves on them in an efficent manner? Just interested to know if you find it effective on tops or just bare logs or trunk wood?