For whatever reason, HN is different to me because, when discussions center around the things that I actually have expertise in, the information tends to be mostly correct. Every now and then some nonsense slips in but, for the most part, keeping people from being able to downvote and upvote everything eventually leads to a pretty informed view of whatever the topic is. Even in instances where I disagree with something, there's usually a well-reasoned response that includes some support whereas, with Reddit, it's just a bunch of unfounded statements with no backup whatsoever.
HN is generally correct about established computer science and tech stuff. Anything frontier or controversial (e.g. bitcoin) or outside the narrow domain of typical Silicon Valley startups gets the exact same ignorant herd response. The point is that when the topic aligns with the expertise of the community you get quality, whereas when the topic varies you get ignorance and BS spoken just as authoritatively. Always be aware of the latter outcome!