Easyship

Easyship is by far the best shipping platform I've used. The only issue I have is that it places duplicate tracking information into my orders. However, that issue could be a conflict with a shipping tracking plugin I use. Regardless, the interface is very easy to navigate and has all the features that you need to create and print shipping labels. You can also set it up to notify your customers of tracking statuses, pickup and delivery confirmations, and other useful tools.