Dry Food: Pros – easy storage and feeding, more energy dense, lower cost, dental benefits.
Cons – lower palatability, more grains, more likely to contain preservatives.
Dry food is by far more convenient and affordable. The food will not spoil if left out. Dry food is also only 10% water. Less water means there is more food per pound supplying your pet with more energy. Larger dogs need more energy than smaller dogs to function hence why larger dogs have a diet primarily (or exclusively of) dry food. Palatability is the taste and texture that makes the food appealing. Dry food cannot compete with wet food in this area. They have lower taste quality but, if your pet is an over eater dry food may help them not eat as much. Dry food contains a high percentage of grains, this is how it can stay good for longer periods of time. While dogs are able to eat berries, roots, and grasses, their bodies don’t digest grains as well. The first two ingredients should be beef, chicken, or lamb. Dry food is easier on teeth because it does not stick to them. Dry food also helps scrape off plaque buildup on teeth as your pet chews.
Wet Food: Pros – increased palatability, contains more protein and fat, easier to eat.
Cons – contributes to weight gain, spoilage, greater cost, and dental issues.
Wet food is favorable toward smaller dogs. They do not require as much energy to go about their daily activities. Wet food also contains more protein and fats that are essential to a dog’s diet. The higher palatability is wonderful if you have a picky eater. Wet food smells better and has a preferred texture over dry food. The food is however more costly and takes up more room. Wet food could cause dental issues. Unlike dry food it sticks to the teeth increasing plaque buildup.
http://www.doghealth.com/nutrition/wet-food-vs-dry-food-for-dogs