You want to know the best thing about CreditKarma.com? It is legitimately free! I have been using their service for a few months now and it is fantastic. They use the Transunion group of the three your credit score is based on. The account you make is free and you do not have to attach any credit card information.
The services they provide include your overall score, vantage, auto, and home scores. All of these scores are important as they can effect whether or not you get approved for any loan. They also have spending analysis including your net worth and money in and out. Much like websites such as Mint.com or PersonalCapital.com you can attach bank accounts, loans, credit cards (that they do not charge), and other asset and liability accounts. They also simulate how your score will lower or heighten and you can compare your use against others of different demographics. Also, like the websites I mentioned, they give you recommendations, which they do receive a commission for if you sign up with one of the services. This is how they keep it free.
What have your experiences with so-called free credit score websites been? What sites do you like to use for your score?