I had a great time in Nagano. The Japanese never leave the groomers, so we were getting fresh tracks 3 days after a huge dump in mid-December, more powder than I ever got anywhere. Nagano is huge, with about 65 lifts, but they are all slow and short, and it's not very steep.
Japan was the strangest place I've ever been, and the best job I ever had. You should definitely go if you have the chance, but not just for the skiing.