HN's primary audience is "hackers", which generally extends to the engineering types. I however have gleaned a lot of insight from comments written by non-coders, particularly those without an engineering background.
If you're one of those, I'd love to hear how you found out about HN and what keeps you coming back.
Link Quality: Articles that are low quality and don't provide any new or noteworthy information are not upvoted by HN and as a result I don't need to take time and energy to sift through them. Almost every mainstream news site on the internet is half full of fluff, and the FB newsfeed is even worse. HN avoids this be having a community of smart people who care enough to vote, and also by not being captive to advertisers
Comments Quality: Concise, rational, well backed up comments get upvoted. If I don't have a pre-formed opinion of a particular article I can turn to the comments to find the smart people who know what they're talking about, and then the best rebuttals right below. If I stay on WSJ I don't see that.
Diversity: Not only does HN cover an incredibly diverse range of topics, but also a diversity of opinion in the comments. Most news sites are siloed by topic, and my FB feed is an echo chamber.
Procrastination Value: Something about HN makes it the ultimate place to go when you don't want to do something else. Your brain gets a jolt from hunting through the list and finding something new and interesting to read. And it updates constantly at a similar pace to meet my procrastination needs. Plus the articles are good so I feel like I actually learned something compared with the Buzzfeed articles I might have clicked if I went to FB.