These were all visited around noon/afternoon on July 17, 2023
(sorry I do not have any good pictures to provide)

We started at Virgin
This was a very big lounge. Lots of good window seats for viewing planes. Very interesting decor.
Food choices were a little limited, all food is table-service. Scan a QR code, they bring the food to your table. No buffet at all.
We ordered the hummus, rigatoni, kale salad, and cookie. All were very good. Definitely get the cookie.
This lounge closed at 1:30 so we did not have much time there. It was not crowded and as I mentioned it is a big lounge.
There is a full bar with a lot of selection. There is a bartender. They might do table service drinks some times. The website had a button for drinks but it did not work.

We then went across the hall to Air India
This lounge is smaller, and has less seating and less window viewing.
However this lounge has the best food. They had a selection of very good Indian food as well as some more western snacks.
I highly recommend going here first as the food was incredible. I honestly do not remember what I had, I had some of everything, and went back for more.
I think they also had some sandwiches, I did not have these because I filled up on Indian food.
There is self-service alcohol here, they had maybe 4-6 spirits, wine, garnishes, etc. They did also have several coolers of soda, juices, and beers.
There are no couches or lounge chairs. All seating is at tables. The only downside here.

We went last to Primeclass
Avoid at all costs, keep on walking. This was a zoo. The food downright sucked, it is full of people on loud speakerphone calls, and children crawling all over your seats.
There isnt even a restroom inside the lounge. They send you out into the terminal. They promised us that we would be let back in after we used the terminal restroom, and then the same desk person hassled us and said that they were at capacity now and told us to get our luggage and leave. We just ignored that and stayed in our seats and nothing happened.
The only positive here is that they have decently comfortable seating. Virgin has better seating but more limited hours.
I would almost prefer the general terminal area to Primeclass.

I would rank them as follows:

1. Air India
2. Virgin
3. Primeclass

If Air India is full, see if they will text you when they have room, and hang out across the hall at Virgin. IIRC they did have a sign of some sort on the desk about a waitlist for peak times.
If more space or terminal viewing is more important to you than food, go to Virgin. The Virgin food was still pretty good and there is much more seating.

Virgin is only open until 1:30pm 7 days a week, so if you are in JFK later in the day, this is not going to be an option. In which case, go to Air India.

Also, on our day anyways, T4 security really was bad. Not sure if this is always the case, we flew out of T5 and it was a breeze, so not sure what was the deal with T4. We have Pre and it still took us half an hour to get through, there were only about 10 people in front of us but the TSA staff were just messing around. Not turning this into a TSA bash thread, but just leave yourself some time if you are visiting T4 for the lounges. JFK's security wait time website was reasonably accurate for T5 wait.