ExcelWriter, part of the OfficeWriter package, lets you deliver customized, data-driven reports, pivot tables, and charts as Excel files without requiring Microsoft Office on the server. The Enterprise version includes components that let users update the server's data from a downloaded spreadsheet.

Databinding in WordWriter is easier because you populate Word's existing mail-merge fields. Be aware that OfficeWriter's documentation uses the term "template" for a regular Excel spreadsheet or Word document that has OfficeWriter formatting. It's not referring to Microsoft's DOT or XLM files.

Your server-side code can create rich documents on the fly with OfficeWriter, including pivot tables in spreadsheets and embedded images in Word documents. Companies moving to SQL Reporting Services will want to investigate OfficeWriter's tools for creating and delivering reports with Microsoft Office.

Data in OfficeWriter doesn't have to be one-way or read-only. ExcelWriter features "HotCells" in worksheets. You mark cells as editable and insert a macro button so users can post their changes back to a remote data source. The data source's URL can be delivered dynamically as an embedded field in the spreadsheet.

ExcelWriter and WordWriter run fine in .NET, but you don't get Xcopy deployment or administrator-free installation. The ExcelApplication object, called when generating a spreadsheet from scratch, uses COM through .NET Interop. For managed code apps, stick to the ExcelTemplate object even though it limits you to inserting data into existing Excel files.

OfficeWriter works as advertised and includes usable, commented samples and adequate documentation. Contact SoftArtisans for pricing on the Enterprise version I tested here. If you choose the Standard edition at $2,795 per server, watch out for missing high-end features and restrictions on how much you can output in a day.