IMHO, the signal-to-noise here is amazing; not perfect, but _so_ much better. If I really want memes or jokes, I'll go back to reddit (and I occasionally do if I want some mindless downtime). I get a lot more insightful information and community interaction here than there.
The karma loss limit of six per comment is also helpful - on reddit you may be hesitant to break with generally expressed opinions over how drastically it can drain your comment - here the two options are -6 or banned (if you're really spewing hate speech).
Also, a shout out to dang for remaining very good at not interfering except when it's really warranted and then shutting things down quick.
I remember a while back when /r/cfb was invited to join the front page and there was considerable pushback from members who were afraid the reddit-wide readership would ruin the quality of posts. Kind of an eternal september thing...