HORRIBLE experience.
First, this is a legit site. It (theoretically) allows you to get your credit report from all three credit report providers once a year, free of charge.
BUT they make it as incredibly painful for you as possible. I am an application developer, and their site fails just about every usability test I can imagine.
1) They use CAPTCHA-style human verification, but they use one with all capital letters. Typically, this type is case-insensitive, but is theirs? Of course not! Of course, they don't bother TELLING you that it's case insensitive, so you put in three bad codes and BOOM! They decide you've had enough fun, and make you start over from the BEGINNING. All the data you entered (the human verification is on the bottom) is wiped out.
2) The site is EXTREMELY counterintuitive, and the "security" questions they ask you are not good ones. If you, for example, pay more on a loan than is required, that might be a bad answer (or not? Who knows? They won't tell you.)
3) There is no opportunity to provide feedback for how badly they are screwing up. They have a "Contact Us" form, but even properly filled out, with all sorts of personal information, and another CAPTCHA trap, it won't accept your data... and after three times of verifying that all the fields they ask for are correct and properly filled in, and clicking submit, it blows away your feedback and makes you start over again, with absolutely no explanation.
Long story short, this is not a "service". This is something the federal government *required* the credit report providers to provide, and they put the absolute minimum effort into actually doing what they were required to do.
There is also no phone number, no email, no opportunity to contact a human to explain the multitudes of problems with this site. Good luck.