I'm no expert on true crime series, having just started watching them this year, but I think this is a very good one. I skipped around at first, watching episodes that looked the most interesting, but ended up watching all the episodes, with the exception of two or three. Except for Season 7, it's a well-done show, complete with a narrator, interviews, actual crime videos and reinactments. Repetition is limited to a line or two after commercial breaks, although I watched it without commercials at Discovery +.
While some of the stories are the same type of crimes, there's enough diversity in those similar stories so that you don't feel you are watching the same crime over and over again. Season 7 was the exception. They obviously were running out of stories to tell, they had no narrator, and some episodes even seemed to be titillating. That was horrible, too, since those episodes involved teenagers being stalked online by perverts. There were no less than three episodes on that topic in Season 7!
After watching this series, I could see some viewers deciding never to use online dating sites, and some watching their kids' online activities like hawks, if they ever even allowed their kids online again. The series is that effective in showing the dangers lurking on the internet. You have so many individuals who would not have been murdered if they only had not gone online, including children. You have so many individuals who would have not been victimized in some other way, if they had not gone online. People online are often not what they seem or who they claim to be.