I've used CK myself regularly for over a year now. Stipulating that the scores are VS 3.0 (even if, right now, they more or less correspond to my FICO scores) and therefore more useful for a general idea of where you stand creditwise than for actual credit-obtaining planning (for which you need FICO scores), and that the card recommendations are often risible, the TU and EQ reports they provide are highly useful and, as others have noted, more detailed in some ways than FICO reports. Also, CK updates every week and sends out prompt alerts of events affecting your credit. It shouldn't be the only tool in your box, but it's still very useful.
