As far as I've been paying attention to presidential elections (probably since 2000), I've always heard candidates' supporters complaining about the MSM being biased against their guy/gal. Kerry, Dubya, McCain, Paul, Obama, Trump, Bernie it doesn't matter.
And they all have bits and pieces of evidence that partly backs up their accusations. However, I think the most compelling argument is looking at which candidate will challenge the MSM's power and privilege the most. And there's a very good argument that Bernie is the one that's the biggest threat to this (regardless of whether he'll actually be able to enact these things).