I'm a regular over on the CX forum, but had a great experience w/ JAL yesterday. Was booked on JAL KOA - NRT, and then on a separate PNR with CX NRT-HKG. The outbound flight NRT-KOA had a medical emergency far into the flight and turned back to NRT, hence the KOA-NRT segment didn't go as scheduled. Despite KOA being an outpost they arranged transportation, hotel bookings for everyone and an $80 food credit within a few hours. It wasn't exactly the Four Seasons, but given the circumstances I thought it was well-handled. They flight ended up being 12 hours delayed, but as I was already going to miss my HKG connection and wouldn't save much time so I decided to fly the next day, 24 hours later. JAL had no problem with that.

In fact, even though the NRT-KOA segment was an award ticket booked through CX (hence CX's ticket), despite me being DM on CX (oneworld Emerald) and calling them 5-6 times it was JAL who eventually solved the problem and rebooked me the following day after the CX agents were completely hopeless to figure out a solution (typical).