I've lived in JC for the past 4+ years and have a lot of friends in Brooklyn and Manhattan, and honestly the real answer on how easy it is to commute is "it depends." Mostly, it depends specifically where you want to go. The further you get from the PATH, the more transfers you have to make, the more miserable the whole exercise becomes.

We have a decent number of friends who live off the 33rd Street PATH line, or are only one transfer at WTC, and these are both very easy trips (the train to WTC is so much faster and so much more predictable than the 33rd Street train, which detours to Hoboken late-night, that a single transfer at WTC is often easier than no transfers using 33rd-via-Hoboken). For these trips, we routinely return via public transit late at night without undue problems.

If you're looking at transferring off the 33rd street line, or multiple transfers from WTC, it's a slog. For that, we usually hire a car. It's not $100 though, more like $60 + tip.