I used HWT this year both with my 7 year old, who needed to work more on her lower case letter formation, and my 4 year old, who started learning to write capitals.
I bought the wood pieces and mat, as well as the slate (all from a GCM
). I also ordered one of their cds, which the kids have enjoyed. The songs give some nice playful ways to help them remember the right formations.
The teachers guides are a good idea. I didn't buy one, but I have a friend who showed me the ropes.
I ordered the preschool book for my 4 year old and the 2nd grade book for my 7-year-old.