Oh, we've beated on this horse a lot.

They all have thier own biases. First rule of human intelligence- your sources have a biases. First rule of pre-digested intelligence- analysts have thier own biases, and thier superiors have thier own agendas.

Multiple sources, preferably ones with different biases. The truth is somewhere in the middle, and the more sources you have the easier it is for you to see it.