I lived in there for three years as single female and apart from the odd attempted grope felt safer on the metro than anywhere else. Fast, cheap, efficient ... and I was generally entertained by the endless ambulant sellers. Only problems are overcrowding at rush-hour, and stares ... White travellers, bar odd backpackers are not the norm. Well-off Mexicans never use it. They claim it's dangerous but I suspected it was more a question of snobbery.

We had a very positive impression of the metro. More efficient than London or Washington DC. Not particularly dirty. Incredibly cheap. Stations full of interest. And we found people very helpful and friendly whenever we got lost. We never felt unsafe or threatened in a week of travelling around the city.