Reliable? On any given year at least one of the major stations is fully or partially closed down. Recently Park Kultury was partially closed for several months, Belorusskaya is probably going to be closed for some time next year. The latter is a very high-traffic station so maybe they will just limit its capacity by 50%. 90% of the time I go via subway, at least one escalator (they are usually in groups of two) is not working, reducing capacity by 50%, with people waiting in a huge line. Sometimes the train will just stop between the stations and stand there for anywhere between 10 minutes and half an hour. Rarely, like once in several months, some shit will happen on Filevskaya line and it will halt for several hours. Underground it's always uncomfortably warm and stuffy – both in summer and in winter. More than enough to get sweaty. The Filevskaya (surface) line, on the contrary, was very cold in the winter (maybe it's better now with the new trains, though). Passenger density of one per square foot in rush hour is also not very comfortable, and when random strangers apply considerable force to push you deeper into the train so that they can get in too, it's also not OK (and it happens in rush hour always, not once a day/week/year). The new trains are simply idiotic. They always smell bad to some extent (they probably chose overly absorbing materials for the floor), they have no place for a map (the few places that could hold it are covered with ads), so the map is posted on the window, and is remarkably unreadable because of the combination of bright white letter outline, an otherwise transparent background, and the fact that you have to lean over a sitting person to see anything unless you have perfect vision and the train is on that rare spot of railroad where the train is not tossed sideways because the tracks are so old.

And it's not cheap. One pass ticket costs nearly $1. It was cheaper to take a bus in LA where median salary is several times higher. The subway is so popular only because it's rather fast with the roads being totally jammed in rush hour (and the buses go with them since there are no dedicated bus lanes). Except for speed, pretty much anything else about Moscow subway is horrid, unless you are a tourist who values the beauty of central stations and was brought there once and in off-peak hour.