We cannot gauge the effectiveness of socialism because it has
never been implemented anywhere in the world. The countries that proclaim themselves to be socialist or communist were and are just full of s__t. State-run capitalist and totalitarian regimes...down to a one. Marx had written that after the revolution there would have to be a brief period of dictatorship over the wealthy few before the socialist state could be fully established. Apparently that has been interpreted as horrifying, rights-abolished murdering mayhem for the next millenium.
Not what Marx had in mind, but anyone who has a brain has already figured that much out.
How can one rate an untested theory? I dunno, so I'll go with a 5 because it is certainly a beautiful one.
The dream isn't over (despite John Lennon's song :-).
Look into the
Socialist Labor Party for an accurate interpretation of Marxism.