What are the advantages over using office automation?

Better Performance

• Office automation can be extremely slow when deployed on the server. It is highly unstable when multiple Excel objects are instantiated on a server. However, XlsIO is designed to work under these circumstances and is a 100% native .NET component, so it can easily handle concurrent requests from multiple users.
• Microsoft itself recommends using third party components like Syncfusion XlsIO in this Knowledge Base article

    http://support.microsoft.com/default.aspx?scid=kb;EN-US;q257757

Easy to use

• XlsIO has a very intuitive and easy to use object model. You can start creating richly formatted spreadsheets in just a few minutes.

Flexible Licensing

• Essential XlsIO has a royalty free licensing model compared to office automation where the end users are expected to have MS Excel licenses when deployed on the server.

 http://support.microsoft.com/default.aspx?scid=kb;EN-US;q243006