If you are looking for a quick and even finish, then spraying with a paint sprayer or decorating paint gun is definitely better. However, it does require an upfront cost for the purchase of the correct sprayer and time to learn how to use it effectively.
Sprayers are ideal for covering textured surfaces, making them perfect for exterior walls, fences, and sheds. They cover these areas extremely quickly and evenly, meaning large surfaces can be completed in very little time.
Generally, we’d recommend DIY decorators to use rollers on smaller interior surfaces, as they require less preparation time than decorating paint sprayers. But if you have a large project—especially outdoors—a Wagner paint sprayer or paint spray gun may be the answer.