The Stanford parser is great, but isn't really the same. The Stanford entity recogniser is limited to the standard types of people, places, companies, but we identify and disambiguate into a far richer ontology from wikipedia, and can recognize topic abstractions that aren't explicitly mentioned.

Also we found the Stanford tools (and the other open source NLP tools) were difficult to integrate into "production" apps for various reasons. One big one was performance - we aim to run the full parsing and extraction pipeline on an average news story in a few hundred milliseconds, which can be an order of magnitude faster than the others.