I've been using Advanced Shipping Manager from King Webmaster (as well as their Centrifuge inventory management system) since 2013. I used the app with my original Yahoo store and now with my Shopify store.

Advanced Shipping Manager lets you customize every aspect of your shipping options. One huge perk is being able to accurately give customers an estimate of when their order will arrive and allowing me to add extra handling days to certain items that might need it. That's huge because if 99% of my items ship the same day from my warehouse but 1% are special order and require 2 extra days of processing time, I want the customer to see that reflected in their delivery estimate. Another big one is making sure the shipping charges are accurate if a customer chooses something like over night shipping. I've seen instances where a shipping calculator might totally miss the actual cost of overnight shipping by $25+. That can be a huge deal, especially if you are shipping a low profit margin item.

Overall I've been more than pleased with Advanced Shipping Manager and King Webmaster in general. They offer good support and will help you resolve and problems you have. Having US based phone support is a HUGE plus over most of the other apps I've used for my store.

We use this app to generate drop ship shipping rates for big distro orders shipped directly from our factory. Since our factory and US warehouse are both in a different time zone we were not always able to provide rates in a prompt manner to our European customers. However, with this app we are able to provide drop ship rates live to our customers, just as if the order was shipping from our warehouse and without having to pick up the extra cost. Recently, we decided to provide a second shipping carrier to our EU customers and needed to duplicate the weight brackets. I contacted Lance and he was able to help us duplicate the shipping rate and all we had to do was edit the pricing. This helped us save a lot of hours we would have spent doing it manually. A few days later Lance contacted me to check everything was working properly and provided further advice with another shipping rate issue. Overall we are pretty happy with the app and the customer service.

This app solved all of our issues with Shop ifys terrible shipping structure. I hesitated to use this app for over a year, if I had not hesitated, I would have profited thousands of dollars on lost shipping revenue. The tech support is outstanding which is a necessity with an app like this.