Several years ago, we needed a way to create Excel workbooks on-the-fly as part of our EQuIS (Environmental Quality Information System) application. Microsoft Excel automation was not an option because we needed the functionality to work on a server platform (which is not supported for Excel automation). Using Excel automation on the desktop platform was excruciatingly slow. We were looking for a .NET managed component and found Syncfusion XlsIO. The product was easy to use, worked in all the desired environments, an performed better than expected (it is very fast). We have continued to use Syncfusion XlsIO over several major version releases and have expanded its use within our own product. Syncfusion technical support has always been responsive and helpful. I have recommended Syncfusion XlsIO to several of our clients, who have also had positive experiences with Syncfusion.