Hi John,
My first reaction is, what is a “mash-up DJ”? Does this mean you’ll only do mashups? In which case you might want to rethink that strategy. There are a few threads on the forum about overdoing anything in DJ-ing, be it mash-ups, FX use, beatmatching, etx.
The mixtape shows you the best way to produce your mixtapes. Good mixtapes make you stand out from the zillion of DJs that don’t bother about things like that. Nobody is gonna listen to a long tape of your mixing if it is poorly done. Also repeating the entire recording til you get it right is a long process. The course shows you a way to be far more effective.
So, if you are looking to put out mixtapes as a tool to spread your “message” and as a marketing tool, then I think this course is definitely worth your money. The only provision is that your mixing, music selection and such needs to be on par. The course does not teach you how to mix or be a good DJ, it only shows you how to make the best possible mixtapes.
Hope that helps.