I live in NYC, and I don't find the coverage to be "poor" outside of Manhattan. There are parts of the other boroughs that are not covered, and those areas are served by the LIRR or express buses. But for the most part I can get almost anywhere I need to go by subway without dealing with a bus.

I used to live in Chicago, and I know conditions are getting more and more miserable as the Ravenswood corridor gets busier every year (and it doesn't help that the reconstruction has started, leading to fewer trains). I was always shocked that only the Red and Blue were 24 hours, but I guess cabs are fairly cheap there....