We are starting to see a major shift in the adoption and demand for open source database solutions in the enterprise.  Scalable, secure and robust open source solutions are now commonly being deployed in SMBs and fortune 500 companies alike.  We work with PostgreSQL and mySQL.  One of the major benefits of an open solution is cost.  Both initial and ongoing yearly licensing often does not come into the equation, TCO can be minimized and capital can be allocated elsewhere or added to the bottom line.