I ended up purchasing the Kaplan CATs last minute, just a week before. Exactly what I needed at the time! I was able to take 4 of the tests before the real D Day. The website is good, decent analytics and software wasn't cluttered. But explanations were brilliant! I made a note of my takeaways, re-read through my Kaplan study material and managed to keep track of my weak areas. Strongly suggest to use these test series, even better to start early. I'm not sure about retaking the CATs though, I don't know how many repeat questions would come up, so some clarity would be useful on that.