I have lost track of how many Earth-like planets have been announced over the past few years. I'm glad we're finding more exoplanets that are closer to what Earth is like, but it seems to me that NASA is just trying to grab headlines (perhaps to ensure it continues to receive public support and funding).
This announcement of a planet -- Kepler 22b -- located 600 light-years away that is about 2.4 times the size of Earth and orbits in the "habitable zone" or "goldilocks zone" of its sun-like star. That's all well and good but to be honest we have only just "discovered" the planet (meaning, scientists are satisfied that they are seeing a blip on the screen and mistaking it for something it's not) and we're not really in a position to make comparisons.
A recent suggestion to come out of the astronomy community to enhance our search for extra-terrestial life is to look for unnatural light from these planets; maybe a civilization out there is lighting up its planet the way we light up Earth. Now that would be something.