It's like asking if you'd rather eat your own poop or a handful of one inch nails. As unpalatable as the former certainly is, the latter is unambiguously worse.
Although I strongly disagree regarding 4chan being unambiguously worse. Maybe if you're talking about just /b/ and /pol/ I'd agree but the site is so much more than that.
For instance, the game development community there much more human and helpful than most other communities I've participated in. But there's a hundreds of other micro communities that are really great if you know where to find them.
I think the chans were cool and interesting back in the early-mid 2000s but since then they've been taken over by not-actually-ironic trolls, political propagandists and astroturfers, and other nasties. Since the forums are anonymous there's no real way to police it or even tell who you're talking to or whether they're a "real person" or a sock puppet of some kind.
I distinctly remember what to me felt like the chans' shark-jumping moment: Ebola Chan.
https://knowyourmeme.com/memes/ebola-chan
When that appeared along with a thread full of seemingly not actually ironic comments like "maybe Ebola will de-populate Africa," I felt that the chans were done.
A lot of people on 4chan view these boards as a sort of filter to scare away outsiders. The majority of the site isn't nearly that edgy and largely discuss the various relevant topics for each respective board.
The problem with most of the internet is that there are so many psychological incentives to repress unpopular opinions and to fit in with the hive mind. Reddit is the pinnacle of that where your opinion is literally shown or hidden based on its popularity. Now this is good for lazy content consumption since most of the time the popular content is what you want to see. But it's also very dangerous. Very very dangerous. Not only because it discourages changes in thinking but also because malicious entities can literally manipulate what you're thinking.
So yes, I may not always like what I read on 4chan. It may act as a platform for mentally ill people. But a lot of greatness also comes from it too. I mean it's no coincidence that a disproportionate amount of internet memes originate there. But a lot of thoughtful discourse also occurs there, often inciting interesting arguments where elsewhere on the internet it'd be buried by downvotes or deleted by moderators.