We have been looking for a high performing docx to pdf tool for a while now. Our system has an e-government aspect and is generating a large number of reports to the user community and performance is paramount. I tried Aspose.Words and I am very happy with the results. First of all, it was very easy and seamless to integrate and deploy in our project. Very smooth. Secondly, the speed of conversion is way better due to the fact that multiple jobs run in parallel. Thirdly, it's not only fast, but there were no formatting errors. Considering that we are providing a multi-lingual system and some reports include both English and Arabic fields (right-to-left alignment!), this was very important.

Finally, the file size was quite small, which again is very important as tens of thousands of documents are created through our system. Before Aspose.Words, our first implementation was Microsoft Office Interop library. This library converts the docx documents to pdf files perfectly, but after a while we noticed that the conversion operations are waiting for each executable. This caused a big delay when converting multiple documents at the same time. One of the reasons for choosing Aspose.Words is that each exe converts their documents to pdf at the same time and no waiting lock exists on the processing time.

Our results show that Aspose.Words for .NET has the best performance compared to other commercial and open source tools.