Saddles come in all shapes and sizes and no one saddle is perfect for everyone. It all depends on how you sit on the bike. If you like to sit upright, you should ride with a wider saddle, since you’re carrying most of your weight on your bottom. If you ride in a more aggressive, leaned over position, you’ll find a narrower saddle will reduce chafing and allow maximum force to the pedals.
The seat is properly adjusted when your leg is slightly bent at the bottom of the pedal stroke. A seat that is too low doesn’t allow your leg muscles to work effectively. Having the seat too high leads to discomfort as your hips rock back and forth while you pedal. Most saddles offer optimal comfort when the seat is level to the ground, so be sure to check this as well.