We're also big fans of the "Key To" workbooks! They were great as a supplement to Singapore, which teaches the concepts very well but doesn't have nearly enough problems to work out for practice. We loved the Key To books for Fractions and Percentages. Each of my kids had problems grasping those concepts and the Key workbooks really did the trick.

We used it for two of my kids and it was very effective. I think the printing is somewhat better than the cursive, however. The cursive just doesn't look particularly attractive, and some of the letters are formed a bit strangely and are a bit hard to read when they write quickly. This is especially now that my son is 12 and writes much faster - I'm actually trying to get him to "unlearn" some of what he did with HWT in order to be able to read what he writes. The K-2 books were great, though! Both my kids had problems with illegible printing, and HWT really did the trick.