The product is very good for connecting to multiple sources of information from different formats like CSV/XML etc., It has helped us in creating custom dashboards which have been quite helpful as we can easily access any reports anytime anywhere using mobile devices or laptops without downloading them first time itself! I would say that there are no major downsides yet but it could be improved by adding more connectors (like Salesforce SFDC connector).
We use this tool daily at work place mainly where our team members connect their excel sheets via FTP into one single folder then extract all required columns through API requests so they don't need Excel anymore just MATILLION does everything else automatically!!