Australia's two socialist parties, Socialist Alliance and Socialist Equality Party, don't seem to get along too well. The SEP feels the Socialist Alliance are capitalist sell outs because they support the Greens. The Socialist Equality Party do seem to be the more hard core of the socialist parties, tracing their origins to Trotsky of Russian revolution fame. In comparison, the Socialist Alliance feel like the university hippy socialist party.
As such, the Socialist Equality Party are very much for the seizing of the means of production on behalf of the workers and fundamentally reworking society, while the Socialist Alliance seem content to work within the current system to promote workers rights and stronger unions.
Since I'm not sure I agree that all of the capitalist system needs to be brought down, of the two I lean towards the Socialist Alliance.