Id argue socialism is a bit of a sliding scale these days. I consider most nation states in the west are socialist in their policies, the USA included (although we shall see how long that lasts). That said, the economic viability of socialism I find illogical over the long haul.
We can look at the USA in numbers to see this. Right now, many services in the USA are provided publicly. They are also provided privately, but that tends to be true the world over. Anyway, the public services are all running out of capital. The USA has over 100 Trillion dollars worth of unfunded liabilities, and is suffering from 20 Trillion dollars worth of debt. Those policies as they stand cannot be maintained.
The same is by and large true for other countries. I'll give another (albeit semi-anecdotal) example. When I was studying at Uni here in the UK about computers, the example of a bad design for a system was the new (and as far as I am aware still being developed) NHS IT System. The system was unusable by the staff, cost billions, and wasn't a decade behind its delivery date when I left university. By every software design and planning measure, it was a failed project, and yet instead of cutting their losses, the state continued to (and as far as I am aware, still continues to) pump good money after bad on this project.
I'll agree socialist concepts sound great. They are well intentioned, and they ought to work to our benefit. But, I feel I must point out Hume's Guillotine here - what Is is not what Ought to be, and vice versa. Claiming something should be X, ergo it must be X is not a valid claim one can make. One must prove those concepts are viable logically at minimum, and the core concepts of socialism (collectivism) is massively illogical.
All that said, the benefit of an free society in the end is that both the socialist solutions and the capitalist ones can voluntarily chosen. People from each camp can choose to associate or not as they see fit with others. With no single reality being forced on all people, all people can determine the best solution for each of them. From my view, free market capitalism provides the most efficient and beneficial solutions, were it to exist, and yes, I would agree as well that actual capitalism is not practised today. What we have today is the bastard child of corporatism(aka fascism as defined by Mussolini himself), state socialism, and oligarchy. Anyone arguing that is an example of capitalism doesn't understand the meaning of the word, or the externalities of the state.
RE: The Social Democratic Case Against Anarchism