[chaostheory]

For things like Rails, that are going to be running all the time, does the JVM warm up time really matter?

[ch4s3]

No, its just a drag to TDD with.

[rurounijones]

I and others have had success with MRI on dev and JVM in prod to get around this.

Maybe not for everyone but as long as you know what you are doing it is viable I think.

[ch4s3]

That's what we do as well. It works well enough.

[Twirrim]

provided you final build, tests and do some sanity checking under JRuby, it should surely meet most needs?