It's one of the most neutral websites I've seen. Of course, since it dares to criticize any tea baggers, they think it's biased. But, it checks everyone.
I tend to agree. Spoiler It's why Fox News' "Fair and Balanced" tag line always sounded Orwellian to me, but that isn't the OP's question. I have found it to be accurate. Is it perfect? No, but I have not been clued into a better source. If someone has one, I'd love to check it out.
I look on everything with some suspicion - Politifact is one of the few sources that I actually trust now.