In his latest, Jacob Santos asks the question more and more people are wanting to know - why hasn't SDO really taken off?

Developers will eventually start using it, it will take some time to go from the PHP way to SDO way. It would be easier to jump into SDO once better, more easily interpreted and simple to understand tutorials, code samples, and support is available. IBM tutorials are a little bit technical, with words and complex pictures (UML). Just give me code and explain how it works and let me run with the SDO scissors in my hand.

He talks about the contributions that both Zend and IBM have made to the effort and the lack of features (well, the duplication of current PHP features - XML and database functionality). He has a positive outlook for the overall future of the project, stating that:

I'm quite sure that enough PHP developers are going to embrace SDO in the coming years depending on the coverage it gets that IBM and Zend's investment will pay off in the end.