The only thing I've ever done to my Winchester, apart from put it in the sleeping bag beside me when out hunting, is clean it and oil it.
Because my 53 year old eyes are turning to crap I fitted an XS Sights ramp and put a Tasco 40mm PDPS Red Dot sight on it. Took that off and have now fitted a Tasco 6 x 40 scope. Took a while to find a side mount for the scope, but I got one. Now all I gotta do is sight it in.
Have never owned a Marlin, but I am familiar with their good name. I believe in the "run what ya brung" adage. If the Marlin turns ya on....go for it. Personally I like the Winchester. Maybe its a history thing, you know, cowboys and indians, but the Winchester just looks and feels like a lever gun should....natural.