Although I have never owned a Japanese or European car, I have owned six Japanese motorcycles, four of them purchased brand new. (Good sample too: One Kawasaki, two Suzukis, and three Hondas. Two enduros, two motocross, one cruiser, and one sport bike.)
I am not sure why the Japanese manufacturers have such a reputation for quality if these bikes were engineered and built to the same standards as their automobiles. The Kawasaki was made from noticeably cheap material (but it was stolen before I could accurately assess it).
One of the Hondas has an intermittent fuel injection problem that doesn’t show up on the codes. Tinkered a little bit with it looking for loose connections but haven’t solved it yet. Even still, I love my Hondas.
The Suzukis were by far the worst. The RM’s clutch basket was made of such soft metal that after a few hours of use develops notches that deprive you of the neutral position. Very annoying. The VZ wiped a big end rod bearing at just under 10,000 miles. All other bearings were pristine, and I had changed the oil and filter regularly. I replaced the crank, rods and bearings, and sure enough, at just a little over 20,000 miles, the same bearing on the same cylinder wiped again.
One the flipside, my mother bought a brand new Chevy Cavalier three or four years ago and it has been very reliable, the only exception being faulty brake light sockets which were the subject of a recall and replaced under warranty. Absolutely no other issuers, she loves it, and drives it all over the place.
I had a ’85 W150 Power Ram 360c.i. I relentlessly abused in my youth that just wouldn’t quit. For example, driving it 5 miles with no coolant, and another time over 100 miles with no oil pressure indicated and less than 1/2 quart of oil in the pan. It kept running thousands and thousands of miles after those incidents. It had over 150,000 miles on it when I had to sell it. Betcha I’d still be driving it today if I still had it.