For the record: we (MongoDB) have a policy of not posting official Benchmarks. I'm not sure what benchmarks you are referring to that were posted and misleading.

The only benchmarks we have ever done have been for internal testing comparisons between different versions.

What information hiding are you referring to?

[edit] The "Benchmarks" page on our site clarifies this policy: http://www.mongodb.org/display/DOCS/Benchmarks

Previously there were several third party benchmarks on this page; but if you examine the page history we have always clarified them as unaffiliated third party sourced.