While this Aquarium blog is a one-stop-shop for anything GlassFish and Java EE from Oracle and from the community, we also maintain a GlassFish for Business blog for those of you interested in making the most of your GlassFish commercial license.
The most recent post there, "Difference between GlassFish Open Source and Commercial Editions", covers just that - why even acquire an Oracle GlassFish Server license? Is is just the support or is there anything more? (hint: there's more).
Another recent post covers the release of Oracle GlassFish Server 3.1.1 Patch 2, a great example of the value for GlassFish customers - a regular cadence of patch releases.
For those interested in finding out more :
• Tech Price List (grep for "GlassFish")
• Commercial GlassFish Offerings from Oracle (how fixes are applied to commercial an open source bits)
• Oracle GlassFish Server and GlassFish Server Open Source Edition (Free vs. commercial, a blog from last year). Being consistent is a good thing (tm).