Good advice. If you know a technology well, then run with it. Focusing on actually delivering value vs. bragging rights to the latest and greatest dynamic language/framework.
On a side-note, I will say this - I am a Java developer (at my day job), and Java-land boasts some of the best tool support there is out there. On the flip side, the refactoring argument does not hold much water. These days almost everything in Java, especially when using any kind of framework means a lot of configuration and wiring using XML, Annotations and other syntaxes (EL - Expression Language comes to mind). Most tools don't see these as live code, so refactoring essentially boils down to a lot of text search and replace.
Java-land is learning a lot from the other communities and products out there. I have been told the Play Framework (http://www.playframework.org/) has some potential but haven't looked at it yet.