The first post was definitely better than the ArsTechnica coverage. However it was not the actual research, the previously linked post was an analysis by a crypto professor from JHU. The work was done by researchers at UNC, UW and RSA, the actual paper can be found here:
that paper is pretty damn impressive - this was a huge amount of work, both in understanding how to exploit an effective side channel, and in the statistical processing used to extract the results from noisy data.
http://www.cs.unc.edu/~reiter/papers/2012/CCS.pdf