It's a very mixed bag.
On one hand, there's people who know a ton about some niche subject you didn't know you wanted to read about but find in some random post about something completely different. I love finding that stuff, actual smart human beings willing to share their knowledge and willing to discuss it like adults.
Then the flipside is the kind of people who post on r/adviceanimals (or "put your shitty opinion on top of a picture of a duck"), all the bots hocking their scams, the misuse of the downvote for "I don't like this" instead of "this doesn't contribute to the discussion" so some actually valid comments get buried and then just people being downright dumb by not being able to explain what they are trying to ask and expecting people to read their minds.
I do love some of the legendary shitposts like basically the
whole post history of u/shittymorph.
Reddit has unfortunately really shittified the service by nearly banning 3rd party mobile apps so it has been in a decline for about half a year, with the low effort bullshit floating to the surface. So far no other service has risen as a viable successor, though Lemmy seems promising and I hope it starts to pick up more steam.