Just started using it today! I have a project that takes a JSON description of a database schema and can emit models in a few languages from that schema. I wanted to add support for a 3rd party application that uses Excel spreadsheets to define its schemas, so I used Excelize to generate the files in the right format.
It was very easy to use; I got it right my first try which is more than I can say for the first time I tried using the OpenXML SDK! Starred in GitHub!