Advanced Shipping Rate Manager

We've been using this app for about a year. Any issues or questions we've had have been quickly addressed by the support team. There does not seem to be a limit to the number of shipping rules you can have. The only thing I would advise to watch for is if you are using the app across multiple stores. If you have two stores open in separate tabs and then open the app in one store, all the shipping rules are copied over to the other store. We have separate shipping rules depending on the store, so we've taken great care to avoid this. Overall, I think the app works very well for our needs!