"They wrote their own BSON implementation which is 10-15 times faster than the one you can download."

Curious to hear more about that one. If true, I hope they open source it, because that could potentially make MongoDB a lot faster for everyone.

EDIT: It's apparently in their vitess code. Relevant code: http://code.google.com/p/vitess/source/browse/#hg%2Fgo%2Fbso...