I just finished a JAL roundtrip BOS-NRT, and flew Cathay BOS-HKG and back last fall, both in business class. Across the board I thought Cathay beat JAL: hard product (JAL seat has better privacy than CX but no storage at all and felt less spacious), service, food (JAL food was considerably worse than Cathay's, especially the Japanese meal which was really disappointing). JAL was almost self-service; all the mandatory service was provided, but not once was I asked, in either direction, whether I wanted any additional drinks or drink refills. They were very accommodating but totally reactive, meaning much use of the call button. CX was much more proactive, offering drinks multiple times throughout the flight and generally anticipating passenger needs much better.

Without a doubt, given a choice, I would take CX over JAL any time.