I live in NYC and am well aware of the so-called 24/7 service. The fact is that it's 24/7 only in midtown Manhattan. If you are on the 1/2/3 or ACE or 4/5/6 lines it's likely you'd get 'For the next 3 weekends services from some outer borough station to 178th street will be suspended from 10PM to 8 AM. Please use the connection bus from blah to blah."

Even the Q line, that is less than 10 years old, went though the same hassle in Feb, and that's squarely in midtown.

The 24/7 claim is exaggerated. Just ask the 7 line folks at the Hudson Yard's end what they think of the claim.

Also, during the weekend I find taking the bus to usually be faster than taking the subway. Literally buses creeping across New York is faster trains.