I was also mostly a lurker on reddit. I found that most comment sections were comprised of cynics and comedians (and, as you said, who ever can make the best pun). The way the karma system rewards these types of posts seems to drown out any real conversation that might of been going on. Hubski seems to me (in my short time here) to have a better structure to support real conversation. I hope that both you and I can grow to enjoy this site and be part of what seems to be an great community.
I've noticed the exact same thing, it seems like the lack of "voting" system really opens up new people who might be scared to post/comment on reddit because of the "downvote if you disagree" mentality that people have there.
I guess people are just sort of vengeful, because they see something they don't like they wanna ruin a person's day. That's why the whole karma thing wasn't important to me, and part of why I only ever upvoted things I liked, rather than upvoting and downvoting. I just like seeing other people's content, maybe adding a comment here or there, but the vindictiveness of the people there wasn't something I really wanted to INVOLVE myself with, I preferred to just sit back and watch. I like to think of a particular quote, I think it was by Voltaire, "I may not like what you say, but I'll defend to the death your right to say it."