1st class vs priority mail is a comparison often made when choosing between USPS shipping options. First-Class Mail is ideal for smaller, lighter packages (up to 13 ounces) and offers a more affordable shipping rate with delivery times ranging from 1 to 5 business days. Priority Mail, on the other hand, is faster, with delivery times typically between 1 to 3 business days, and includes tracking and insurance. The choice between the two depends on the size, weight, and urgency of the package.