I've always used myfico.com. It costs a bit, but they give you great, easy to follow information. Based on the thread though I just tried out creditkarma. Very nice for free.
Just tried http://quizzle.com based on Experian data. It's also free and considered "soft inquiry" so as not to affect your credit score. They only allow 2 free reports per year, however, unlike creditkarma which allows you to update your score daily.
www.creditsesame.com - Free score based on Experian this is a FAKOS score not your FICO score but it is close. www.creditkarma.com free score based on Transunion this is also a FAKOS score www.myfico.com will give you the actual FICO scores for Transunion and Equifax, they used to give Experian but Experian now does not make it available. Even the score from Experian.com is a FAKOS score and not FICO
Lol, I pay for my scores and reports from all three reporting bureaus, and I checked this site for the hell of it. It says my score is 84 points lower than the paid reports I receive.