What can a subjectivist say makes free markets preferable?

When I ask Austrians what makes markets desirable, I often hear the answer the line about markets "allocating goods to their highest-valued use." But any consistent subjectivist knows that we can't make interpersonal comparisons of utility/value, which means there is no "highest-valued use." What, then, can we say markets do or tend to do that makes them desirable to alternatives? We might say that markets make best use of dispersed and inarticulate knowledge, but what does this mean as a result? What general statement can we say about the markets' outcomes that is consistent when the school's foundational subjective theory of value. In short, my question is: What can an Austrian say markets do? Why choose markets?

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