I think Zach is on the right track. I was thinking, even simpler:
PostgreSQL: Reliable. Advanced. Open. Free.
Although "Open" could also be "Professional", "Compliant" (SQL 99),
"Adaptive", "Flexible".
Too bad there isn't a single word for
"you-don't-need-a-PO-and-a-dozen-forms-from-the-deniers-of-IT-and-6-months-to-install-and-use-it".