A few things seem pretty stark.

1. Definitely crappy mods banning people across communities for bizarre or literally no reason, like not even having posted there. Those bans happen constantly and randomly.

The mods also remove posts constantly and arbitrarily.

ml mods also span literally dozens of communities, using different usernames so that they control huge parts of ml.

So if they don't like your brownie recipe in the cooking ml community, they ban you for months across all two dozen communities that they moderate.

There are crappy mods everywhere, but ml mods aren't even pretending to develop or maintain communities, they're a very small group of assholes controlling the largest communities pushing their weight around for fun

This results in stagnant, circle jerk communities that feel very stale.

2. There's no content moderation, so you have to constantly point out that headlines they're copying and pasting are factually incorrect before a conversation can begin.

This also results in stale, unproductive threads.

On the off chance you do stumble across a good conversation, it's surrounded by a much higher rate of boring fundamental geography where you have to prove that South Korea is actually a country before the person you're talking to will even accept the news article written about South Korea is real.

3. And then the communities are extremely toxic.

Since the mods communities don't have to follow any rules except being nice or listening to the mods that you are personal friends with, you can explicitly personally insult people who disagree with you and the mods will do nothing about it even though that's explicitly against the rules and it diminishes productive conversation.

Especially if that user is friends with one of the shitty mods, they'll just point you out and you'll be automatically banned because their cousin doesn't like your username or something.

Those are three big ones off the top of my head that I personally don't like about ml

4. Since I blocked all of the ml news sites, the quality of the news articles and the discussions about the articles is like night and day.

The ml "news" is often ridiculous biased nonsense that you can't even address other than "That's an objectively false statement" or " The article says nothing of relevance at all and the headline is irrelevant to the content of the article".

After blocking ml, the news on lemmy went from like 30% legitimate to 70% legitimate in a flash.

I didn't do the math, but I do feel like I'm coming across twice as many relevant news articles as I was before and people are making intelligent, considered comments in those communities.

Not so in ml