I rode on the PATH for the first time on Saturday (2 days ago). I wanted to document my experience. I didn't take any notes and I am writing this without doing any research. So probably don't trust this blog post very much.
The PATH is a ??? train ??? subway ??? that connects Manhattan to some parts of NJ. Which parts? I'm not sure! I imagine most/all of the populated bits on the edge next to NYC are probably connected, but I'm not sure how far deep into NJ it goes. I spent $3 to go on it one way, although initially I went to the wrong platform and had to spend an additional $3. This was devestating.
Sights
The PATH is noticeably cleaner than the subway system in NYC. It also feels more industrial - I stood next to a large panel that was for overriding the doors, and it looked like it came out of a factory. Unfortunately I didn't take a picture but it was pretty nifty.
Next to the door controls was a window that was at a good height to look out of while standing. I was pretty pleased about this - on the NYC subway the standing-height windows only exist on doors. And that means if you want to look out them, you need to get out of the way every stop (and potentially fight to get back to where you were standing before).
The PATH is underground though (or at least, the section I was on was), so the window view can be a bit boring. The main exception to this is where you get to an intersection-y part and you can see all the other tracks and tunnels.
Sounds
The PATH has some pretty cool sounds. I don't think the tracks are welded, because there's a very nice clack-clack noise as you travel that the subways in NYC don't have.
Instead of the "stand clear of the closing doors, please" that I'm used to in NYC, the voice on the PATH just says "stand clear of the closing doors". I think it is a bit rude to not say please.
The voice is also different. Unfortunately I don't remember in what ways it differed, just that I preferred the NYC voice.
Conclusion
good job!