Stop selectively reading through your ideological lens.
My evidence is "the technology that Cassandra uses"--that is, the SSTable/BigTable storage format and the Amazon Dynamo eventual consistency and distribution model--has been not only peer reviewed and published, but has been serving for years as the foundation of two of the busiest Internet websites in the world. That's real world experience orders of magnitude more extensive and robust than the anything MongoDB can offer.
> Amazon, Google, Facebook throw mass engineers at problems Cassandra has overlapped with.
> There for, Cassandra is better than "database written by amateurs"
If you have hard evidence post the fucking evidence.