I tried once, but didn't get Tor to work, so I left it that way.
From what I know, the majority of it is just databases that simply don't get tracked by search engines. There also seems to be a bunch of places for people who really want anonymity (forums for people who fell victim to specific crimes, etc.).
I've also heard that the amount of illegal sites on the dark web is not as big as people make it out to be. So, basically any type of "knowledge" about how terrible the dark web is, is probably coupled with a lot of misinformation and lack of knowledge.
Would I be interested to try it out sometime? Sure, I'm from Europe afterall. We gotta figure out some way to keep some freedom on the internet. Therefor any option that provides that freedom is one to be considered.