Stability. One of the major goals with XLSReadWriteII was to create a product that won't corrupt the Excel files and won't alter any data in the file. The engine that handles XLSX files is automatically built directly from the file format specifications with our special developed tool. This will ensure maximum comatibility. No runtime fees for the component. Full source code included.
We released the first version of XLSReadWrite in 1998. At that time it was the only component that could read and write Excel 97+ files. We are commited to have the leading Excel solution for Delphi in the future as well.