There are many differences IMO. Moderators, for instance, censor a ton on reddit; but the UI is also different. I much preferred old.reddit.com over both the new reddit (which is utter trash) and hackernews (which is simple, but also ... strange and awkward, much more confusing than old.reddit.com - and I hate the fact that after like 5 comments, I get locked out for hours before I can make more comments, that is the worst decision hackernews ever made).