I've purchased a bunch of videos back when I got into Sonar, I maybe got a few tips but nothing I couldn't have figured out myself by reading the manual.
I think part of the problem is that we don't see ourselves as knowledgeable as we are.
Most people here, according to what I read, are WAY above beginner, even though we tend to see ourselves differently, so when we buy a training series we are bound to be disappointed, as none of them are for the really hardcore nitty gritty stuff.
I buy a tutorial video once in a while for mixing, specific instruments etc.., but having been in the whole DAW/Studio game since cubase, Studio vision on mac or Dr.T on atari and amiga and in and out of studios since the 80s, there's nothing new anymore, and I just find myself skipping chapter after chapter, feeling like I wasted my money, and that's not really the fault of the authors, I just didn't pay attention to what I was getting.
I also have a problem with naming conventions, masterclass?... and then a little while in, it's about how to set up a buss, that's more like babbys first DAW class.
I wish some of the industry top dogs would release something in their particular fields, I'd have my CC out in a flash.