A leather collar will necessitate extra care. If your dog is outside a lot and the collar gets wet/dirty, it will rot faster. It will need to be cleaned and treated with leather care products to maximize its life. When the collar begins to wear, it has a greater chance of breaking than a nylon one.
You might want to look into loose-leash training to reduce your dog's pulling. Since, he's a big, strong breed, I wouldn't worry so much about him getting hurt. I used to have a black lab who was a puller, and he didn't even feel the collar - lol! I ended up getting a Halti (head collar) to make our walks more pleasurable. After that, a young child could walk him with no problem. Every dog is different, though.
You might want to look into loose-leash training to reduce your dog's pulling. Since, he's a big, strong breed, I wouldn't worry so much about him getting hurt. I used to have a black lab who was a puller, and he didn't even feel the collar - lol! I ended up getting a Halti (head collar) to make our walks more pleasurable. After that, a young child could walk him with no problem. Every dog is different, though.