The Embraer new generation jets (170, 175, and 190) are not in service yet. As far as I know, 170 is in advanced certification tests, the 175 is in early certification tests, and the 190 has not flown yet.
JetBlue bought the EMB190. I read here a few weeks ago that Embraer was flying the 170 to some of JetBlue's bases so the employees could get a look at the new type of aircraft that they will be getting. I don't know if they were going to paint a 170 on JetBlue's colors for this, but if you saw "some" JetBlue planes at JFK
, they were probably the Airbuses.