GoDataFeed is incredibly responsive and super knowledgeable of the capabilities of their tool. They have been able custom build all datafeeds that we've thrown at them.

I'm using Godatafeed for the typical stuff but also for wilder applications. I'm using it to do calculations and logic to create an advanced feed for our shipping solution that uses a flat file to configure shipping. Between Godatafeed and our shipping solution I have create broad and granular rules to do things like "if profit is less than $300 and package cubic volume is over 4000 remove free shipping". It's been an invaluable tool to improve the data quality of various feeds for my ecommerce store clients. I'm also using their supplementary feed tools. I import additional data from client ERP's via FTP so we have data beyond what's in Shopify. It's updated daily so the values are fresh. This allows my clients to not spend a fortune on Zapier requests or rely on 3rd party API's for this data. 5 stars for Go Data Feed and their support is great.

Free one-time assistance setting up the Google Merchant Feed was a great help.