Dd and I loved Preparing :001_wub: but neither of us were as thrilled with CTC. DD found Preparing pretty easy but struggled with CTC so we shelved for 6 months and picked it up again when she turned 11.
Ultimately it came down to the book choices in CTC. They are all worthwhile books but drier than I was expecting after doing Preparing. I thought they were challenging for the recommended ages and a big step up from Preparing. DD didn't really relate to the story time books... from memory there seemed to be a lot of books with male characters.
We got through it but I think she would have got more out of it if she had been older.
FWIW, Preparing is the only "packaged" curriculum I have really loved. And it's not that I didn't like CTC; I just didn't love it.