Less about appearance and more about function, I went to Moscow as an American in 2013. The thing that really blew me away was the fact that trains came pretty much on the minute, so there was no schedule. You just wait a little bit and a train comes by.

The other really cool thing was the Yandex app for routing on the system, which a) worked completely offline, and b) would show you which car of a train to get on and off (and at which doors) to make the most efficient transfer between trains at stations. Simply stunning.