I've had and/or lived with three dogs over the course of my life, and those were among the happier years I remember more fondly than others. Companionship and someone to play or even exercise with was always available, and that benefit is hard to put into words. Most dogs are unconditionally loving and very loyal. There's also a safety factor in knowing your four-legged friend will start barking incessantly at unwanted visitors on your property. I always slept better with a dog in the home.
Still, there are drawbacks. Dogs are expensive at times, and they are also a commitment. You have to dog-proof your property and home, lest they break things and injure themselves. And they cost more than just dog food. Immunizations and vet bills add up, and are as regular as a person's own medical costs. Dogs also need time and attention, more so than cats. This time and attention is one of the benefits, but it also eats up a lot of your schedule. You'll get more activity and exercise, but you might not always feel like taking them out to do their business on late winter nights. You might also have to clean up after them.
Training is essential, even if expensive. Also, if you rent, you may have to pay additional fees or put a deposit down before getting a pet. You also have to have dog-sitting available if you travel out of town without your pets.
All in all, having a dog has a lot of benefit, but is also a lot of work. Before you can even get one, you have to make the decision between a rescue pet, adopting a local puppy or buying an animal. Personally, I would recommend a rescue dog if you can provide a good home to one.