I'm travelling with a student VISA to Pittsburgh. I'm flying from Lisbon and the flight connections are to Newark, Boston or Philadelphia. I would like to know if there's an "ideal" option between these. In order to avoid delays getting stuck in long lines and missing the next flight.
I'd go with Boston of those three options, but it is hugely dependent on time of day, and what other flights arrive before/after your arrival, but for your connections, the most important thing is layover time. I'd try to maximize layover time, so while Boston has less traffic (only slightly from PHL) (significantly from Newark), if you can get an extra 20 minutes on your Philadelphia layover, I'd take that. Also, just reading the tripadvisor forums, people generally report 40 mins to get through customs in Boston, a little under an hour in Philly, a dab over an hour at Newark, at peak times.
Source for preference: professional experience
I would also go with Boston, as years ago, I got through immigration pretty quickly. However, it may be more important to determine whether you will have to change terminals, and/or whether you can check through your baggage.
In any case, give sufficient time for the transfer; depending on the connecting flight and airline, give even a bit more, or you may be stranded for the day (if bad comes to worse).