Shipstation is the perfect shipping tool!
I love how easy Shipstation has made it for me to buy postage and print labels. It has synced with my Squarespace store and has made the whole shipping process very automated and simple. When an order comes in, it just takes a couple clicks and then I have a nice looking pre-paid label to stick on the box.
Easy to use, time-saving. It integrates well with my Squarespace site. When there are sales I just go to my Shipstation page, make a couple of clicks, and I have a nice official label to stick on my package, with the tracking info automatically sent to the buyer.
No real cons that I can think of...Perhaps the fact that it is a separate site that needs to be accessed instead of being built into my Squarespace account is a con, but that fault probably lies with Squarespace and what they will allow.
It was easier to use, integrated with Squarespace, and didn't have the same bugs I was encountering with PayPal's multi-order shipping tool.
Saves time on shipping
I would highly recommend ShipStation to anyone with an online store.