Not to derail your thread, which I enjoy very much.

but here is some thoughts from Stalin... on this very topic
Where does this quotation come from?
Ever since Marxism came into being, there have been true and false Marxists in the Marxist movement. The whole history of this movement is full of struggles between these two groups. Similarly, the Marxist movement in China has also been full of such struggles. This must be thoroughly understood by all our Party members.
Twenty years ago, Stalin correctly described these two groups. Let me quote him here in full:
There are two groups of Marxists. Both work under the flag of Marxism and consider themselves 'genuinely' Marxist. Nevertheless, they are by no means identical. More, a veritable gulf divides them, for their methods of work are diametrically opposed to each other.
The first group usually confines itself to an outward acceptance, to a ceremonial avowal of Marxism. Being unable or unwilling to grasp the essence of Marxism, being unable or unwilling to put it into practice, it converts the living, revolutionary principles of Marxism into lifeless, meaningless formulas. It does not base its activities on experience, on what practical work teaches, but on quotations from Marx. It does not derive its instructions and direction from an analysis of living reality, but from analogies and historical parallels. Discrepancy between word and deed is the chief malady of this group. Hence the disillusionment and perpetual grudge against fate, which time and again lets it down and makes a "dupe" of it. The name for this group is Menshevism (in Russia), opportunism (in Europe). Comrade Tyszka (Jogiches) described this group very aptly at the London Congress when he said that it does not stand by, but lies down on the point of view of Marxism.
The second group, on the contrary, attaches prime importance not to the outward acceptance of Marxism, but to its realization, its application in practice. What this group chiefly concentrates its attention on is determining the ways and means of realizing Marxism that best answer the situation, and changing these ways and means as the situation changes. It does not derive its directions and instructions from historical analogies and parallels, but from a study of surrounding conditions. It does not base its activities on quotations and maxims, but on practical experience, testing every step by experience, learning from its mistakes and teaching others how to build a new life. That, in fact, explains why there is no discrepancy between word and deed in the activities of this group, and why the teachings of Marx completely retain their living, revolutionary force. To this group may be fully applied Marx's saying that Marxists cannot rest content with interpreting the world, but must go further and change it. The name of this group is Bolshevism, communism. The organizer and leader of this group is V. I. Lenin.
it just seems to me its hard to tell which group is which now days...
Well first, let me say that I think Stalin is full of [feces]. What this quote amounts to is that they want to use the name of Marx to justify their actions, but don't want to restrict themselves to following what he actually says. Thus, they demonize people who do, and create excuses for themselves for their deviations, as well as play that classic idealist/realist card that gets used so much
against communists and their kin.
Any reading of Marxism should yield an expressly clear lack of application to Russia as it existed in 1917. That's why Trotsky came up with the theory of the Permanent Revolution, so that Marxism could be adapted to the Russian situation. It was this adaptation that Lenin built his April Theses upon (aka, a rejection of the classical Marxists, who were the Mensheviks, who wanted to follow the policy we have together described above with regards to the Chinese Communist Party, and a continuation forward with the socialist revolution before a mature capitalist society existed, the economic progress of which they would imitate themselves); at no point did either of those two men pretend that they were following an orthodox Marxist understanding of correct action. This was why, when challenged by Kautsky and Luxemburg on this very issue, Lenin's response was that
they did not understand and appreciate the unique situation the Russian communists found themselves in, and thus their orthodox Marxism was incapable of leading them to the correct answers -
with regards to Russia. He did not say that they were following the One True Path of Marxism as opposed to Western European supine Marxism. This also did not stop the Russians during the 1920s from supporting, for example, the Kuomintang
over the Chinese Communist Party, an expressly stagist policy in direct contradiction to what Stalin has said above is the only correct action.
What Stalin is expressing above is one of the foundational principles of Marxism-Leninism:
the path of the Soviet Union is the one true and correct path for all of society to take from capitalism and imperialism to socialism. It is not based upon an understanding of either Lenin nor Marx, but rather a justification for the hodge-podge regime that resulted in the USSR because of both its historical path, as well as the efforts by Stalin to consolidate his own power, and his successors and their political class to maintain it. It is one of the main reasons why Marxist-Leninists have no place imposing their ideology upon the communist parties of advanced capitalist nations like the United States, because our situation and history is wholly different from that experienced by Russia in 1917. They are espousing the defensive ideology created by one man and his
caudillos as it was required of another country 80 years ago, not even a useful understanding of Marxist or ante-Marxist ideas today.
I realize the above puts me firmly in that supine Marxist category Stalin described. I don't care, because it's a stupid distinction. Sure, there are "Marxists" who are all talk (the type of people described by the quote in my signature about philosophy and opportunity) and lack a clear understanding that Marxism as the Philosophy of Praxis means that we actually have to think about how to really do stuff, and also people who do think about such practical matters as Making Revolution, but who lack either/or the philosophical, sociological, economic and ideological background. But the reality is that we need to guide ourselves towards a "Marxist
phronesis," with a balanced understanding of both the academic as well as the practical sides of things. Pretending one is more important than the other is a good way to divide your forces, and as communists, that is the absolute last thing we can afford to do.
EDIT: I have realized that I did not respond to your post, merely the quote you included. I have edited the quotations in this post to reflect that reality.
... especially since the USSR made so many mistakes in its advancement of communism...
Socialism. The Soviets never claimed to have created communism.
it seems that Menshevism would not have changed China's dirrection on its still to come 100 year march forward.
As I have already hinted above, Stalin's explanation of Menshevik ideology is ridiculous. The Menshevik program was to allow capitalism to happen in Russia, but under the watchful eye of communists who could shut it down whenever they wished, and would do so when it had outlived its usefulness in getting them to the socialist starting point. Lenin's point of departure from them in April was that 1. they were collaborating with the Provisional Government, who were liberal capitalists, and not really taking actions to properly exert the sort of control they said was necessary to carry out their program, and 2. that there would be no guarantee of such a capability of power to shut down capitalism when that time came, and that at the present they did have that capability, and so the opportunity to establish socialist rule and nip capitalism in the bud should not be squandered. Trotsky's program simply provided Lenin with the capability to theoretically equal the economic development that which the Mensheviks could have theoretically allowed capitalism to do.
That was confusing grammar. I hope all that made sense.