So- I gave this a try with my own money. I'm fascinated by book boxes. Amazon gets points for letting you choose the books - not any books, but you get a few choices for each book. They have age groups, and I decided to use the 9-12 age group.
I liked the selection process as you get a full description of each book and you can make sure that your box does not contain books you already own. The price point is $22.99, which isn't bad for two new hardcovers. They arrive in a plain old Amazon box (I'm a sucker for pretty graphics, so the box made me sad.) Although, usually an Amazon box is a pretty magnificent sight- I guess I have different expectations in a "book box."
Unlike Owl Crate Jr or BYL Family Book Crate which have monthly themes and the contents are a surprise, Amazon is more low key. You choose the books from a limited selection, no special box or packaging and no extras. I'm okay with no extras as I'm anti-clutter and usually we end up regifting or donating the extras anyway. They are fun to Instagram, but we rarely keep them so in the end the Amazon box is the best fit for us and I still don't like it. I guess I want the unboxing experience more than I realized.
I'm not getting crates over the Summer months at all unless I see something extraordinary in the theming, but I did consider using OwlCrate as part of our LA studies next school year. I generally like their selections, and I love their swag. I took the Percy Jackson pillowcase for myself. I'd also get the family crate from BYL again if the theming were right for us.