[jmnicolas]

Postgres is better than SQL Server because with Postgres I always have the "awesome edition" : http://blog.codinghorror.com/oh-you-wanted-awesome-edition/

And I don't need a certification to understand the crazy MS licensing (I discovered recently that yes there is a MS certification program for their licenses as it's so byzantine).

[andrewl]

I remember Jeff Atwood talking about this in a Stackoverflow podcast. With Postgres or other free software, you not only don't have to lay out cash, you also don't have to spend time trying to understand arcane licensing rules. (And worrying that you might have violated one of them.) Whether the time (and time is money) saved balances out the cost of the software when the commercial product offers better functionality will vary with the situation.

For what it's worth, Atwood chose Postgres for his Discourse product. The FAQ says the product is "Uncompromisingly open source." And "There is only one version of Discourse--the awesome version. There's no super secret special paid commercial version with better or more complete features."