Why open source? As a pro developer, the time saved (and time is often much more costly than a License) on a proprietary CMS may best serve myself and the clie

Why open source? As a pro developer, the time saved (and time is often much more costly than a License) on a proprietary CMS may best serve myself and the client. You should not limit your available tools. And of course, different tools work better for different jobs. For most things, I prefer ExpressionEngine.