(Disclaimer: I'm a postgres community member.) I think the biggest advantages are trust and flexibility. Trust, because PostgreSQL language semantics are clea

(Disclaimer: I'm a postgres community member.) I think the biggest advantages are trust and flexibility. Trust, because PostgreSQL language semantics are cleaner, closer to the SQL standard, and less likely to surprise you. And postgresql just has a good reputation for traditional engineering quality. Flexibility, because it offers a lot of APIs and features that can be very useful to adapt your application as needs change. You don't have to go crazy with features, but even simple apps can benefit a lot from prudent use of them -- a trigger here, a foreign table there, or LISTEN/NOTIFY (for cache invalidation) can just save you a huge amount of work and make the system more robust overall. The extension mechanism is very powerful. Before making any big decisions, do a trial migration and see what you think.