I don't think the results of Aphyr's MongoDB and postgres experiments are directly comparable. In the OP, MongoDB was run in a 5 node replicated configuration.

I don't think the results of Aphyr's MongoDB and postgres experiments are directly comparable. In the OP, MongoDB was run in a 5 node replicated configuration. In the post you reference, the experiment was run against a single postgres node. Furthermore, the postgres experiment only checked that no writes were lost. As Aphyr acknowledges, MongoDB did not lose any writes with "majority" write concern. The postgres experiment did not include the verification of a linearizable history of reads, which is what the bulk of the OP is about. I'd like to see a similar experiment run against a replicated postgres configuration with auto-failover.