Both breeds rate 5/5 with children and 4/5 with strangers, and both are genuinely safe, warm dogs. Neither is a guard dog; the Newfoundland's 2/5 barking rating makes it the quieter of the two by some distance.
The temperament keywords tell the real story. The Newfoundland is described as sweet, patient, devoted and calm — and calm is the word that matters. It is famously tolerant, slow to react and physically gentle for its size, which is why the breed has such a reputation with small children. The Malamute is friendly, loyal, playful and devoted: warm, but busier, and physically boisterous in a way the Newfoundland is not.
On trainability the Newfoundland leads 4/5 to 3/5, and the gap is real. It is a biddable working breed that wants to cooperate, takes to draft and water work readily, and is soft enough that harsh handling backfires. The Malamute understands the instruction and then weighs it, which is why off-lead reliability is a goal most Malamute owners never fully reach.
On solitude and beginners the Newfoundland is also ahead — 3/5 against 2/5 on both. It is not an all-day dog, but a normal working day with company either side is within range, and a committed first-time owner can succeed with one in a way that is harder with a Malamute.
Where the Newfoundland is more demanding is emotionally. It is a leaning, following, physically affectionate breed that wants to be in the room, and 130 pounds of that has consequences for furniture, doorways and anyone carrying a hot drink. The Malamute is affectionate on its own terms and comfortable being separate.
With other dogs the Newfoundland leads 4/5 to 3/5. Around cats it is generally safe, while the Malamute's hunting drive stays live.