In most cases, I think all of us would have to say guilty go free. However, there really is no way to fully determine your answer without circumstances, so let’s add some and see what we might choose.
Suppose the guilty man were some sort of homicidal maniac, like say the Green River Killer. Perhaps it is not so much that society would choose to set him free as it is that he is free because he has not been caught.
And suppose the innocent man is indicted for a misdemeanor of petty theft, which, if convicted, would have the man spend somewhere between a few days to a year in prison.
By setting the guilty man free in this case, then will not innocent lives perhaps be preyed upon if this man continues his murderous rampage? It then becomes a question of the lesser of two evils, right?
Just a thought.