Like with most academic publishers, Bond gradually build up their materials over the years and you'd notice that they favour certain topics than others, which may or may not fully reflect the 11+ exams that your DS will be sitting.
A sound approach is to go for balance and variety: be selective in what you want to get out of the Bond papers and then identify areas or topics that your DS might find interesting or difficult and source different materials to help your DS to practise them.
Personally, I find Bond papers very clear and well laid out, though sometimes a bit predictable .. you should always allow for a bit of "unpredictability" from the actual 11+ exams
You'd need to be careful with the 11+ exam type (standard versus MC) for your DS. Exam techniques are quite different for these two different types of exams.
Once your DS has gained enough confidence working with Bond papers, you might like to continue working with More Fifth papers or even Sixth papers. They are quite challenging but can also test your DS's deeper topic understanding. Again, you should try to be selective.