Earlier this monthly I flew JAL 009 (ORD-NRT) and 010 (NRT-ORD) in business class with this configuration. For what its worth, I left ORD on Sunday and returned from NRT on Sunday, so maybe it is a day-of-the-week issue? I also have an upcoming flight on JAL 009 on a Thursday with the same configuration, returning on JAL 010 on a Friday with the "normal" configuration.
Anyway, I sat in 36K both ways, bulkhead of the third cabin. On ORD-NRT, there were 3 passengers in the entire cabin (out of 36 seats). My impression is that the other two cabins were much more full. With the attentive service and silent cabin, that is high up on my list of favorite flights. The way back was more crowded, and 36H was actually occupied.
The only drawback to the third cabin is the view. You are smack in the middle of the wing. Next time I'm in 9A/C (flying with Ms. Underwater), but I think I like the back of the front of the bus.
-uw