[MoOmer]

Some counterpoints:

2. You have access to troves of Java libraries from most JVM languages.

3. Again, not all JVM languages suffer from this.

4. Some JVM languages have a REPL. JRuby and Scala for example.

5. You can use Ruby on Rails out of the box with JRuby and Torquebox. A couple of gemfile changes and you're good to go.

[Chris2048]

2 & 3 aren't really counterpoints - 3) explicitly states "If you go pure Java", and 2) regards compatibility issues, not lack of libraries.

[ericfrederich]

I believe Django also works under Jython

[Chris2048]

Last I used it it had a memory-leak issue that persisted for quite a while. By the time the bug was fixed, I'd gone off it.