I have an third grader that is just about to finish TT3 (slated to finish the first week of April) and should finish Beast 3D by the end of May. I absolutely LOVE using these two in tandem. TT hits on some things that Beast doesn't and vice versa. Yes, TT is much simpler than Beast (BA is for advanced students) but seems to be very thorough yet doesn't go into depth. My daughter seems to fly through TT with little interaction from me. Since Beast is more challenging, we do the guide together and I absolutely love the growth mindset that Beast promotes with the starred problems that really make her have to think hard. I would definitely recommend using these two together. My daughter used to not really like math, but now says it's her favorite subject.