We used this product on a project which required tight Excel integration with our ASP.NET application. This project has been running reliably for almost 2 years. Users download data which is dynamically inserted into an Excel workbook and downloaded to their machine all in-memory. Users can also upload data in XLSX format for processing. This tool has exceeded our expectations. Not only is it a good product but SyncFusion has proven to be a company that we can rely on. The support that we have received is definitely 5 stars. I recently contacted the support team with a question about how to execute some specific functionality. Not only did my question get answered the same day but I was also provided with runnable sample code! I highly recommend XlsIO as well as Syncfusion to any company.