I'm generally happy with the O'Reilly books I've bought. What they cover depends on the book.

Some, particularly some of the language or OS books, are reference-oriented. Not the kind of thing you'd necessarily read straight through.

Some, the "intro" books, are just what that sounds like. Enough material to get started.

I don't know if I have any O'Reilly books I'd consider "deep", exactly, but I don't think they really aim at that.

In general, my experience is the books are what the titles say they are.