You see, PSOL has some popularity, as it stood as an viable alternative during the Presidential elections of Brazil (Even if they got little votes - I won't enter in details, the post is big enough) and they believe they are capable of radicalizing it. (It's NOT entryism, they plan to really build the party, but leftwards.)
So, in your opinion, which works out best between these two strategies, or what works even better than these? I accept any contributions, provided it's not an one-liner saying how you know much more than me, blablabla, go read Marx, blablabla.
It depends on what you want to do really. But just this brief comment, I don't get it how this doesn't constitute entryism? It's a basically entryist tactic, to collectively join a larger workers' party and work within it, either as a "mole" who expects being thrown out but leaving with more recruits for their communist organization (which was the idea of Trots here where I live), or actually expecting to build that organization and steer other people to the left.
If it's not entryism, that means this Marxist Left would renounce even informal faction status, as an intra-party group with specific views.
So, what you want to do? I know it seems weird, but this is really crucial. If you want to join an organization with some established contacts among the unions and the working class, and further work with these people on what seems as basically an electoralist basis (maybe also helping out workers and other folks gain small gains in the meantime ), then go ahead. I don't think that such a basis can have an effect of escalating class struggle beyond some point when it is recuperated (and mostly it is recuperated and redirected into election of honest social democratic politicians; see SYRIZA).
FKA LinksRadikal
The possibility of securing for every member of society, by means of socialized production, an existence not only fully sufficient materially, and becoming day by day more full, but an existence guaranteeing to all the free development and exercise of their physical and mental faculties this possibility is now for the first time here, but it is here. Friedrich Engels
"The proletariat is its struggle; and its struggles have to this day not led it beyond class society, but deeper into it." Friends of the Classless Society
"Your life is survived by your deeds" - Steve von Till