what is united states postal service ground advantage is a USPS service that combines affordability with reliable delivery times for packages. Ground Advantage is used for shipping larger or heavier items and is often more cost-effective than Priority Mail for non-urgent shipments. This service provides tracking and delivery within 1-5 business days, depending on the destination. USPS Ground Advantage is a solid choice for e-commerce businesses looking to save on shipping costs without compromising delivery reliability.