Perhaps that's true, but put the same amount of effort into a Mauser (which is unnecessary, by the way) and you would probably get a corresponding improvement.
I believe the OP wanted to discuss the two rifles as they were put into service... not what they COULD become with lots of TLC.
Wrap the barrel in oiled felt? What?? Where do you even FIND oiled felt? How do you keep the oil from getting all over everything? What does it do? Do you wrap it tightly? Counter-clockwise? How often do you have to change the oil?
If you were to shoot pre-WWII specimens, one of each, chances are good the Mosin-Nagant would have the edge right from the factory (and I say pre-WWII because quality was going to crap on both sides, especially from '42 on).
As for the felt thing:
1. Find felt at Walmart or your fabric store of choice.
2. Lightly oil it.
3. Tightly wrap it around the barrel until it fits tightly between the handguard and lower forearm.
Floating a barrel is a good thing -- IF it's not a pencil-thin military barrel. If it is
a military barrel, you want to try to make it one with the handguard to eliminate harmonics as much as possible. I use rubberized cork gasket material. The Soviet Snipers used felt -- same idea.
In fact, many German snipers tossed their 'scoped K98s in favor of the Mosin-Nagant sniper's rifle when fighting over that way. A bit more precise and not nearly so many problems in inclement weather as the Mauser.
The Mauser does have improved ergonomics and a stronger extractor, but that's really about it.