I originally used stream readers. And the test results above are for stream readers. But then I needed to get the DTD publicId/systemId and with stream readers I couldn't. Although I haven't tried getPIData(), I assumed it's for processing instructions. In the the standard StAX API there is general getText() and in case of JDK impl it returns something like "couldn't get the DTD info" and in case of Woodstox - just an empty string.
The only way I've found to get publicId/systemId so far is by using event readers and Woodstox-specific API.
I haven't run the performance comparison tests for streams vs events yet as I wanted to make it work for the metadata and the AS first.