awesome!! JFK-BOS is a combination 320/190 route as mentioned above. This is mainly for capacity. Some thought jetBlue was nuts to start 10x E190 JFK-BOS saying "no one will fly it...blah blah blah"...1.5 years later and this route is one of the best performers for jetBlue!
I've yet to fly on the E190

but I made myself a promise to do so this summer! Even if it's just a day trip. I am doing it with a friend of mine who is a fellow FlyerTalker, so if you're reading this...get read for the E190 this summer!