We're having two discussions in parallel: on the objective value of Reddit given its circumstances, and on our own personal taste for using it. You're probably much better off in many ways for not visiting.
I would like to know how informed abstainers see Reddit. I feel like given some contrived option to identify themselves with the heritage of their birth culture or nationality, or by their careers, or by where they would fit into traditional subcultures, very many Redditors would identify as Redditors, by interests and attitudes in common with a sufficient critical mass, even with dissent. The Colbert/Stewart rally, more than the individual acts of kindness, has fed a zeitgeist within Reddit that they are a community awakening to their own political power. Momentum is currently building to a campaign in protest against the TSA (which will probably fizzle, with much disillusionment for all). But I think 4chan has showed online subcultures with some chaotic convergence of will can increasingly effect the world outside their own community. And I can't conceive of any way a community, online or off, could come to be sufficiently large to find political feet, and turn out any better than Reddit has.
Regarding HN:
HN still has a higher signal-noise ratio, but as HN gets more popular (with many coming from Reddit, I presume -- and going the other way, as I did), I find that the difference between HN and applicable sub-reddits is dissolving. In particular, I feel like there was some suppression of humour on HN that has weakened since I arrived, which as lame as it seems was a not insignificant differentiating factor.