Tokyo and all the Japanese metros - Very clean, simple to use and I love Suica card scan to enter thru the turnstiles and also doubles to buy food, drink from the vending machines and shops in the station. And also the people on the metro are quiet

Madrid, Barcelona, San Francisco, Vancouver, Toronto, Montreal, Sydney - Clean and easy to use. Stations and trains had signs and lighted charts to show you where you, what's the next station and which direction you are going.

Worst
New York City - I found it confusing to use. I always ending up going the wrong direction or on the wrong train. I went through 3 bottles of mini hand sanitizers when using the fare machines. Stations that kinda resembles a sewer...uncollected garbage that now looks like sewage on the train tracks and water dripping from the ceiling of the station.

On my upcoming trips, I'll be using Chicago, Milan, Zurich metros for the first time. Let's see how punctual those Swiss trains really are.