I definitely see benefits of Java over either of those languages, but each to their own.
The fact remains that you will spend 80% of your time working on content rather than code. Whatever you can do to reduce the burdens you're putting on yourself is worth doing...
I see enourmous benefits as well but the assortment of engines is very inferior compared to C++.
In every other department (except maybe speed) Java is the winner.
Right now there is not a single full fledged gameengine in Java, only a few (quite good fortunately) graphics libraries.
Still going to stick with Java cause it's brilliant and I for darn sure aint leaving Eclipse for VS or some other annoyance