USPS Media Mail takes 2-10 days for delivery. The holiday season/winter months can possibly delay delivery (2-14 days).
USPS First Class takes 2-7 days for delivery. Also with the possibility of slight delays during the holiday season/winter months.
USPS Priority Mail is usually very fast, 2-4 days.
USPS First Class International usually takes 2 weeks for delivery with many possible reason for delay. Additionally, Registered Mail, while more secure and guaranteed, can also delay the delivery process.