I have had few discussions with Objectivists and read few other discussions where Objectivists took part and I haven't seen particularly high level of rationality there. Objectivism as actually practiced is a political ideology with all downsides - fallacious arguments of all kinds, tight connection between beliefs and personal identity, regarding any opposition as a threat to morality by default and so on.

Agreed. I'll also note that several of the Objectivists who I've shown LW have reacted positively, often saying things along the lines of "this is what I wanted out of Objectivism."