The distinction Hoppe makes between the so-called "clean" capitalism where the laborer and capitalist enjoy a mutually beneficial, symbiotic relationship, and the parasitic, exploitative capitalism that Marx critiques is a valid and important contribution. Marx's straw man of capitalism, in which exploitative laborer practices or corporatist conspiracies between state and firm, provide evidence to support the false thesis that the free market is somehow inherently orientated towards corruption continues to exist in the popular imagination of the Left to this day.
However Hoppe's article also repeats a lot of the same fallacies as Marx's Manifesto, namely its insistence on characterizing the history of all of civilization in the reductionist terms of some black and white, epic, cyclical class war. I don't agree with Hoppe's assertion that Marxist class theory is more or less true, just arrived at from a false starting point. I'm still not convinced that it was ever true to begin with, regardless of the logical steps taken to reach the conclusion.
Marxist class distinction is far too fuzzy a social construct to be the unifying theory behind history, economics, or any other social science that it wants to be. Hoppe's insistence on working from within the same flawed framework as Marx frustrated me and only seemed to lend credence to the cynical idea that the Austrian school is simply the Marxism of the Right.