This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
When I set up my environment at my hosting company a few years back, I chose PostgreSQL over MySQL since, at least at the time, MySQL did not have transaction support. That may have changed since; I haven't really kept up since Postgres satisfies my DB needs completely.
Another thing I really like about Postgres is its support of the LIMIT and OFFSET keywords which make serving up large datasets as 'pages' almost trivial. I don't know if MySQL has added such support or not.