What do the plot and conflicts in Animal Farm suggest about kinds of governments that Orwell admired and detested?

The plot of George Orwell's Animal Farm makes a very strong statement about Orwell's position on different forms of government, particularly those he finds detestable.  Tired of their servitude to man, some farm animals carry out a revolution to gain the ability to run things for themselves.  This is essentially the argument for most revolutions.  Those revolutions, the purpose of which is to slough off an oppressive regime, often turn to socialism, lured by its emphasis on the more widespread dissemination of power among the population - government on a social level.

This seems to be the direction the farm is going; however, the pigs trick the other animals into another form of servitude.  The pigs use the slogan "All animals are equal, but some animals are more equal than others."  The first part of the statement is perfectly consistent with a socialist outlook.  The second part of the statement, however, indicates that the new power structure is another version of what is seeks to replace.

Participating in the Spanish Civil War during the 1930s, Orwell had direct experience of Communism, surmising that Communist leaders predicated their actions on deceit and dishonesty.  The pigs' deception is emblematic of his view of Communism.  In the example of the pigs, particularly their rhetoric, Orwell clearly demonstrates that from the promise of equality for all comes exceptions for some - the promise of socialism is replaced by the realities of Communism.

In his depiction of the events in Animal Farm, Orwell clearly advocates a form of republicanism, a system in which every person has a direct say in the matter of government.  While Orwell indicates little that would expresses this admiration, the manner in which he depicts Communism, particularly those aspects of Communism that serve to distinguish it from socialism, is rather telling.