ORIGINAL: cma3366a
Rifle magazine just did a piece on the 454puma. One thing to be aware of is that they are a bit finicky about the loads they will cycle. Their sample would not cycle .45colt, unless the bullet was seated to 454 OAL; nor would it cycle loads with an OAL longer than 1.760". They also ran into trouble with certain bullets such as the winchester 250gr factory load. As a reloadfer you'll be able to get around this, but its something to be aware of. They also mention that the stock became loose several times throughout the test, and required loc-tite to fix.
In that case, I might go with the Marlin. I get quickly irritated with with guns that are finicky about what they will cycle. I'll have to pick up that copy of Rifle, sounds like an interesting edition.