I worked with some ATS training years ago (it was on a System/38) and we currently have some Manta Training.
The ATS was very basic at times, but very thorough. I haven’t had any experience with it in the last several years, but I’ve read some positive reviews. (Sorry, but I don’t remember where I read about it.)
The Manta training that we’ve have definitely can lean to the basics. But it will take someone with very little experience in the area and can get them productive if they move with the training. It’s been benficial to some of my other developers, but it’s fallen short in areas where I’ve sought to gain increased understanding.
Just my personal experience