We recently stayed 2 nights at the Hilton Newark Penn station, having chosen this hotel for its proximity to the railway station because we were travelling out on Amtrak.
There is good access to New York City on either New Jersey Transit or PATH. NJ Transit to New York Penn Station is more expensive but quicker, although it is actually 18-19 minutes (timetable) and not the 10 minutes that another reviewer has quoted. Also, NJ Transit trains don't run as often as PATH so when you take waiting time into account, it can take longer.
We caught the free shuttle from Newark Airport to the hotel and were very impressed by the welcome we received from the driver. It's a pity the shuttles only run once an hour though. You have to take the AirTrain to the area where hotel shuttles pick up and there didn't look to be a taxi rank there, so if you missed the shuttle you would either have to wait an hour or get the AirTrain back to where you could get a taxi.
The room was pretty much standard Hilton, very comfortable and well-appointed. All the staff we met were friendly and helpful. We enjoyed dinner in the restaurant, but breakfast was the worst meal I've ever been served anywhere in the US – it took a long time to arrive, despite there only being 2 other diners when we arrived, and was inedible, and it takes some doing to mess up breakfast. Fortunately we had been given a breakfast voucher so were not paying for the meal, which I certainly would not have done.
As another reviewer has noted, the concierge lounge is closed on weekends. There is no mention of this on their website, it was not highlighted when I booked a Concierge room on a weekend, and it wasn't even mentioned at check in. I only found out when I walked past the lounge, was puzzled to see it closed, and read the opening hours on the door. I was extremely annoyed about this because I had specifically chosen, and paid for, a Concierge room so we would have access to the lounge when we arrived at the hotel after a long flight on Saturday, and after a long day walking around New York City on Sunday. There is absolutely no difference in the rooms other than lounge access, so I feel I was conned into paying extra for a service that it was known would not available.
Although it wasn't explained as such, I presume the breakfast voucher we were given was in lieu of the continental breakfast which we should have been able to get in the lounge – hence we only had one voucher although we were staying 2 nights (the lounge was open on Monday morning). But, as I've already said, the breakfast was inedible. And even if it had been okay, the cost of one breakfast each didn't cover the difference between a standard room and the Concierge room I had booked, and certainly didn't adequately compensate for the lack of the lounge on Saturday and Sunday.
Overall, I would stay at the hotel again if in the area, I just wouldn't book a Concierge room. And it has adversely affected my opinion of Hilton. I believe the website should clearly state that the lounge is not available on weekends, and it should be highlighted when anyone tries to book a Concierge room on a weekend.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.