Useful Charts has some solid content. From what I've seen it's well-researched, but like anything on YouTube from a random person you should verify important facts you care about. He's good about correcting (almost always very minor) errors in follow-up videos, but the fact that he had to occasionally do those talks you something.
He's interesting to me because personally he has a Christian background but converted to Judaism, but he also does well-researched educational material as his day job, so he presents info well.
I think the more direct inspiration was Gus March-Phillips. The recent movie "The Ministry of Ungentlemanly Warfare" is a fictionalized telling of the work that the team Ian Fleming was on, based of some of the recently declassified missions.
Either way, if you're interested in the topic it's a really fun movie.