Speaking as somebody who no longer has cable and thus doesn't watch any of those, I can call out what I've observed:
NBC has been caught in deliberate lies when they want to alter a story to fit their narrative. See the George Zimmerman 911 tape editing job they did, for example. If that isn't blatant lying, I don't know what is, yet for whatever reason you don't see any sites like foxnewsboycott.com target them.
CBS -- remember memogate? The investigator behind the story, Mary Mapes, actually found that Bush volunteered for service in Vietnam but was declined by one of his officers, but that tidbit was never revealed until a year or so after Rather was already fired. Instead they chose to broadcast some memo which they were unable to (and I think never did?) authenticate. But both of these are neither here nor there; what I find more disturbing is that the whole point of all of this was to derail an election, and actual "news" had nothing to do with it (I mean honestly, who gives a fuck about a service term that happened some 35ish years prior and was otherwise unremarkable?)
The best (worst?) argument I've seen against Fox actually didn't involve Fox News, rather it involved an entirely separate news organization that happened to be a Fox affiliated broadcaster. The common argument goes something to the effect of "Fox sued for the right to lie" but when you dig further, you actually find that the plaintiff (not Fox or the local affiliate) was suing for the right to lie, namely the local broadcaster didn't want to air the piece unless they had both sides of the particular story (something involving Monsanto, I don't recall) but the plaintiff refused, instead only wanting to push what amounted to a one sided hit-piece. How that got twisted into "Fox sued for the right to lie" I'll never quite understand, especially given that the Fox affiliate didn't even initiate the lawsuit.