Hi, yes, we used these with our DD1 and are now using them with DD2. I think they're very good. You are right that book 1 is for younger children. We started DD2 on book 7 last year (year 4) and she is currently doing book 9. The language is sometimes old fashioned, but a lot of the vocabulary in verbal reasoning does seem to be old fashioned. I would think they would be great for improving comprehension as well as you have to fit the words into sentences and crosswords, and sometimes the sentences are peculiar english 'figures of speech' that modern children haven't come across yet.
Thanks Pixiequeen, that was very helpful