Marxism is probably preferable to the feudal society these guys are promoting.
That's an interesting comparison. Ignoring the question of whether "these guys" are promoting feudalism, I find it interesting to think about which actually is better, Marxism or feudalism, as an economic system.
From an ideological perspective, Marxism is better, in theory at least, because placing all ownership of property in the hands of a few lords is blatantly unfair. From a practical perspective, though, I'm not sure there's a difference, because every attempt to implement Marxism on any scale larger than a small commune ends up putting control of all property in the hands of a few committee members. I don't think there is any real difference between ownership and control that looks just like ownership but isn't.
In both cases, what you have is central planning, normally organized on multiple tiers to address the fact that no one person or committee can understand and manage it all. However, feudal systems tend to create stronger demarcations between the tiers, and very strong separation of control between the fiefs. This allows for the development of a market economy between fiefs, plus whatever internal markets the feudal lords choose to allow. And those who allow greater economic freedom will find their fiefs generating greater wealth, and feudalism is, er, not much constrained by ideological considerations.
I suppose a Marxist nation that organized itself as a collection of small communes who engaged in market transactions between one another could do that as well, but I think the ideology tends to squash that idea, because if communal ownership works at the small scale, why not expand it?
All in all, though neither is a very effective economic structure, I suspect that feudalism would be better than Marxism given comparable levels of technology and education. Marx obviously thought his system would be an improvement, since his whole focus was transitioning from feudalism to the "improved" world of communal ownership. But I think history has proved that he was simply wrong.