I've visited reddit a fair number of times and haven't found much use for it over other sites. The comments on reddit are typically about as valuable as those on 4chan with the modification that they are on average less entertaining and also contain fewer pictures of genitalia (on average).
People who generally comment on reddit's childish comments based on their time on the main reddits and rarely visits the meat of reddit, which are the specific and targeted sub-reddit, are fly-by users. They never truly experienced reddit.
It already did, alas. A couple of years ago it was really nice, but even when selecting only a few potentially interesting reddits (programming, science, etc), some posts are OK but comments are more and more both useless and stupid.
So finally I spend much more time on HN now. Though the problem is that probably most older reddit users will come there, then pushing the HN old-timers to start some alternate HN-clone :)
You may learn some things about these cycles of "I was on Site X and it was great, then went to crap, then I went to Site Y, then it went to crap..." which will surprise you, and which -- at least in my reading and based on my experience of spending the last decade building community-oriented sites -- hint that reddit's doing way, way better than HN.
Am I the only one seeing a huge chunk of Viagra spam ("A proposito viagra 50 mg di pazienti affetti da malattie coronariche 10,8-11,8 arteria laureato rilevando ...") in the middle of that article?
Will there be any paid gaming of Reddit?
Will Reddit turn into a sewer as it grows, as did Digg?