They key issues in the discussion of the BICEP2 result center around the way BICEP2 accounted for dust in the foreground.  They based their analysis on a presentation graphic which was shown at the April APS conference of 2013.  This may have been a mistake.  In the defense of the BICEP2 team, that graphic was the best data available at the time.  A .fits file of this particular data from PLANCK did not exist yet. Never the less, it leads to reasonable questions about the validity of the result. When I asked the B-mode question at the April APS conference in 2013 the answer from the spokesperson of the PLANCK collaboration was that there may not be a detection of the CMB based on their preliminary analyses. 

In brief, the problem(s) with BICEP2:
Foreground, foreground, foreground.  
  •  Background VS Foreground. To see the CMB one needs to understand and eliminate all foreground sources of microwave radiation. This means everything else in the universe, in particular emissions from our own galaxy. For much more detail see ("Toward an Understanding of Foreground Emission in the BICEP2 Region" Raphael Flauger, J. Colin Hill, David N. Spergel).
  • The BICEP2 team relied on a presentation graphic prepared by the PLANCK team which seemed to characterize the foreground dust emissions.  BICEP2 then computationally subtracted this image of the foreground dust from their data to arrive at a measurement.  It could be said this is partially the fault of the PLANCK team for not sharing the raw data openly at the time.  They are very open about their data products in the long run.
  • The open question is did the BICEP2 team properly remove the foreground.  If not, then their observation proves nothing.  If so, then their leaders will end up getting a Nobel prize along with Alan Guth.
  • Only the PLANCK collaboration with it's great resources can confirm or invalidate BICEP2's results.  Only they have the resources to accurately measure the foreground, and computationally subtract it from their image to get the actual CMB.  In science observation rules supreme. 

The situation is summed up nicely by Nature's headline... no evidence for or against gravitational waves 
I hope the BICEP2 teams result is confirmed.  It's really not looking good right now.