Here's the thing about DA... it's extremely complicated to categorize, just like art itself. DA basically boils down to, "What is art?" DA is like the single source on the entire planet where that question is fought (besides the whole video game art situation.)
So when you go to DA, plan on trying to realize that art is extremely subjective and just because you don't like what you see, or are offended... that's too bad. Art is art and it boils down to intention.
So are you going to see great art? Yeah. Will you see a lot of adult content? Yeah. Will you see everything in between? Yep. Does the adult content filter work? Most of the time. Can you get the moderators to take care of business when there are seriously violent / criminal acts being posted? Yes but they're a tad on the slow side due to staffing. They seem to get to it about as fast as Twitter does.
DA is only ever going to be as mature as the people that visit. As long as a mature audience is there holding the line, DA is going to be the beacon for art on the internet but if we get frustrated and leave we're going to lose it and never get it back again.
Please come to DA, help keep it clean and in perspective where your knowledge is strongest, otherwise try not to be offended just because you don't like something. And if you see something violent, do the right thing and report it.