I think the command economy part of communism (the governance form) is probably the biggest problem libertarians have with communism. I don't think they have anything against equal partnerships between large numbers of people.
Oddly, that part came mainly from capitalists; the early-20th-century Marxist idea of "scientific management" of a centralized industrial economy was closely modeled on scientific-management ideas from large industrial conglomerates.
There was a period when large industrialists were arguing that having many competing companies is inefficient, and instead managing a large, integrated industrial sector via scientifically/mathematically sophisticated methods was the future. That was one argument against anti-trust laws: that breaking up large companies would just decrease efficiency. The only thing the communists really disagreed with was what should be done with the profits of these trusts.
> biggest problem libertarians have with communism
is ignorance of communism et al actually means. At least for the masses of "don't tax me bro!" tea baggers and other modern bandwagon, pseudo libertarians.
