[Arubalisa]

American flies both:
ERJ-140 ERD (seats 44) & ERJ-135 ER3 (seats 37) from BOS-JFK.
Economy Class: pitch 31.0" width 17.3" seating details 37 seats, this configuration is the same as the 757. Given the choice of the convenience of flying a smaller jet for the same seating, I would chose the Embraer anyday!