For me personally, the books have helped me see what I don't know. I have the Chemistry 1001 book and I do about 25 problems a day (it doesn't take very long to do) and if I get a question wrong, I review the content. Then I cross-check the topics with the AAMC section outline to see if it's a topic I should consider reviewing, and go over it until I'm sure I won't get it wrong again. In my opinion, it's much less stressful content review method since I don't time myself, yet I'm able to figure out what concepts I know/don't know.
In a nutshell, they're good for content review if you have more time and want less stress. I would use them if you are tired of your study routine yet still want to refresh the material in your head.