What would be the strongest reasons for running Drupal on PostgreSQL, in terms of available features and performance? I.e. what postgres features of that are supported by Drupal are not available on mysql? For example, postgres is known for ACID conformance and transactions; does Drupal core take advantage of these or other features in any way?
This question is not about which is a better DB in general, rather whether there are any specific reasons why one might choose postgres over mysql. One obvious trade-off is that many contrib modules will be buggy running on postgres.
I am working with D6, but feel free to direct answers to any major version.