I don't hate this book.

There are several things in it that I enjoy, particularly several of the archetypes, particularly the Fighter and Monk ones.

However, certain parts of this book just don't entirely strike me as feeling Spelljammer-y. Moreso, certain things, like the Cybernetics/Augmentations or the Artificer's Spellwalker archetype (Which evokes the old Elven Spirit Warriors in a way that is just- ... less fantasy and more sci-fi) and the like feel more akin to something you'd find in Paizo's Starfinder setting. While this isn't bad, I do feel it veers a bit too heavily into the 'technology' facet of the world, something that Spelljammer back in 2e avoided pretty well. Overall, I'd allow some of this supplement at my table, but each thing would require individual approval.

Is it worth $9.95? Maybe, I'm more okay with that price than I would be if it were say, $14.95, but overall I have to say my take on this product is a hard 'maybe', some good, some bewildering.