Little difference I find. Both equally congested. Transfer times and costs to NYC about the same.

I find JFK slightly easier, I am no fan of public transport by any means but in NYC it is easier to use the tube to JFK than a taxi to EWR or JFK.

Last time, I departed from JFK on 23rd Dec and caught the 7pm flight - I left at 4pm and got to the airport for 6:45!! only managed to get on my flight because the cabin crew were delayed in the same traffic too.

EWR I have only used once, and I remember it took forever and no taxi would pick me up (even less willing than a taxi to JFK)

I've only ever been to Newark , but had no problems on both occasions. Plenty of taxis outside terminal with prices displayed. On the return journey the hotel concierge asked us if we wanted a car to the airport, and it cost no more than a taxi. Just make sure you give yourself plenty of time, especially in rush hour. Go for the best deal from any airport.

Ive done JFK and i have my first flight to Newark in February.

JFK was really easy to and from the airport, plenty of taxi's outside waiting but you have to be careful as there were a few people in and around the arrivals area touting for fairs and they weren't taxi drivers, just people bringing their own cars to the airport.

My advice is go straight to the marked taxi rank and jump in a yellow cab.