A couple friends of mine (and some FTers) suggest to NOT take NYC subway after midnight because it is not safe. So, I've been trying to catch a cab whenever I go clubbing in NYC. However, NYC cab drivers at night are snobby and they sometimes refuse to take you to your destination

So, one time, I decided to take the subway (9 from TS to Grand Central, and also 4, 5, 6) on a Sunday night. It was about 1:30am and there were still quite a few people on the subway so I felt safe. This was in early September so I don't know if that made a difference.
So, is NYC subway safe after midnight?