Upvoted for the opposing observations. I have taken KTX but I have not taken (non-subway) rail in Japan. The KTX train I took was similar in quality to German

Upvoted for the opposing observations. I have taken KTX but I have not taken (non-subway) rail in Japan. The KTX train I took was similar in quality to German inter-city rail or American regional rail lines. That is to say, it wasn't that special. The air quality issues are a huge pain for sure.