A lot has been written about the benefits of Open XML. In my own words, here is my short list of the key benefits.
It’s a standard, free for all to use, and extremely well documented. In my job, I’ve had to research, explain, or write code samples for the markup in a wide variety of areas. I’ve yet to come across markup that I couldn’t figure out quickly. In particular, the DII site is a great way to read the standard and understand its implementation in Office 2007.
The ability to save, load, and use the document format in a wide variety of applications and tools means that we have document interoperability in a way we’ve never seen before. In my opinion, we have barely scratched the surface with regards to interoperability. As I accumulate more and more tools that work with the format, life becomes simpler.
The ability to convert binary documents to Open XML with a high degree of fidelity means that companies who have literally millions of documents can convert them, and ‘light up’ these existing documents. This enables folks to do stuff like implement their own custom document crawler or indexer that meets needs that a standardized crawler can’t meet.
This benefit is particularly important to me personally. All you need to work with Open XML is a library that can open and save zip files, and some sort of XML parser/processor. One key aspect of this benefit is that it is straightforward to make tools that run server-side. XML processors are the stuff servers are made of – they are specifically designed to perform well, not leak memory, and reduce security risks. I regularly hear about scenarios that are straightforward to address with a custom Open XML processing tool. And of course, the Open XML SDK rocks!
Integration of Business Data
Separation of semantic data from presentation markup is a core aspect of good document format design. I regularly see interesting solutions that custom XML parts enable.
I really appreciate that a DOCX file doesn’t contain macros. If it does, Office 2007 will refuse to open it. Of course, Office 2007 is great at telling us if a DOC file contains macros and disabling them by default; even so, I still get a funny feeling when I need to open a binary document from an unknown source. But DOCX files? It’s not a problem – they just contain presentation markup.
Smaller File Size
This particular benefit is key to people who manage all variety of document stores, including Exchange servers, SharePoint, and of course network file storage.