A DM works if it is reliable and goes in smoothly and positively every time. I've been disappointed with some of the Remington products. ( I sold them for 6 months about 5 years ago)
The thing is can you do it under stress every time - like, you're driving around the bend, and ther's the moose of your dreams walking towards the bush. Try practicing inserting the loaded mag AND reefing one in the chamber from the inserted mag, then retry with an empty mag in the gun and tossing a round in the chamber like you can with a regular non DM magazine. If you can, try that exercise, fire at a target, then rechamber a round, either using the full mag or empty mag and some other ammo source. Try to introduce a bit of stress in the situation, then see what your time and hits are.
For me , hunting, no question, travelling with an open action, tossing a round in ,firing is a lot faster. your mileage may vary....