I only skimmed one part, the 'Socially Necessary Labor'-segment, and... at least the first criticism read like a (willful, perhaps) misunderstanding of the concept as Marx described it. The second is about practical implementation, and how that was basically impossible in the soviet union and the last is about how it's hard to measure (duh, it's a theoretical concept for the most part; mostly useful in the conception of further theory).

If the other criticisms follow a similar line, they'll take one micro-aspect of Marxist theory and then lament how that aspect, in isolation, isn't getting you anywhere.