Many years ago I dropped my UC-Hexanon 35/2 and damaged the helicoid. Sent it to 3 technicians in the US, all of the highest prestige, to no avail after half a year and $$$ spent. Eventually sent it to Kanto and was told some of the repairs messed up the otherwise fixable helicoid but they'll do what they could. The result wasn't bad at all - just a bit coarse during action. Almost a decade later, When I dropped my second UC-Hexanon (gosh), I sent it to Kanto without hesitation. They fashioned a new helicoid and planted it into the lens. I could only gasp at the marvel.
They also repainted my 35cron v1 back then. A few years later I sent the lens to them to have its internal elements recoated (!) and the lost infinity lock replaced - they make their own parts but have agreement with Leica that they'd only include them as part of a service. All top notch job.
On the other hand...I sent via a friend a FM3a with dead meter to Nikon Japan. It was 2016, so extra nice of them to be still supporting an old model. The camera was fixed, supposedly CLAed and came with a warranty. Only until I (carelessly) sold it off to another friend did I realize the camera metered but wouldn't do AE. Turned out that Nikon's technician, when installing the shutter button, misplaced it in a tricky position that the shutter actuates before the meter activates, so the camera would think it's extra long exposure regardless of the lighting condition. As the camera had to be sent to Ginza in person to claim the warranty, I just didn't bother and had a local technician fixed it for a small fee.
So, a bit of mixed experience for me, even with Japan. Guess things just happen regardless of nationality.