I stopped putting any stock in RCP after their prolonged insistence that Romney was going to win, right up until the bitter end.
My dismissal of them is purely anecdotal, but there’s been like four or five races over time that I cared about where they were telling me one (comfortable, ultimately untrue or skewed) thing, and other sources and reality let me down by being correct.
As much as I hate their editorial content, I go with FiveThirtyEight.com for poll data. Their track record is pretty good.
As you can see above, their mighty average can be easily swayed by any polling firm surveying their favorite 200 RINOs and adding that to the mix....