When it comes to pricing, Charlton is a fairly good guide. It is at least quite a bit better than the Standard Catalogue of World Paper Money (SCWPM) IMO (which is so often overly optimistic or completely out to lunch low). But it is a guide that helps with a starting point. On some earlier series there can be pretty large discrepancies between what some notes command at auction & what the guide lists. Sometimes increases due to US collector demand (especially for older series) can outstrip the editorial's staff's ability to update. But that's the case with any guide.
When it comes to data on each BOC (& most DOC) series it's pretty authoritative or somewhat accurate. I think the notes & advice it offers is critical for collectors to pay attention to. Obviously, there'll always be emerging data requiring revisions. But that's just the nature of the hobby as it evolves over time.
