I checked out the Jal F lounge today (well hidden in the main area ).
Yeah it's a nice lounge. I think whiskey lovers will be happy - there must be about 10 whiskeys there of various descriptions.
The showers are absolutely amazing

Definately worth a visit.
The buffet is ok, but I would prefer more western options. I got the feeling though that I was a 'weird' visitor (wasn't flying Jal, wasn't a Jal member etc) and looked at a little strangely. Oh well, the staff were friendly about it.
Now back in the Qantas lounge, and about to stroll/train to the AA lounge. Both these are reasonable lounges, but nothing special at all!