How does the way holmes handles the perpetrators of the crimes affect the way you view holmes? is he entirely admirable? is he somehow "above the law"? is his behavior ethical? why or why not?

This is a strong opinion question, so the answer depends tons on your own opinion. Personally, I think Holmes has his own version of justice, and he applies it where he feels it is more beneficial than the actual law. In the case of "The Adventure of the Specked Band," you'll remember that the guilty party was killed, and so there couldn't be any arrests made then. But with "The Boscombe Valley Mystery," Holmes was able to "deduce" that to turn Mr. Turner in would cause more harm in the situation than to give him a severe warning. If you'll look back on it, you'll remember that Mr. Turner was all but begging Holmes not to turn him in, solely for his daughter. Holmes must have known that turning in Mr. Turner would cause so much more trouble for the family than they really needed. Besides, Mr. Turner was in fact willing to follow through with the law, though he said otherwise. He was a sick old man and knew his time was coming to a close, and he didn't want to fight anymore. 

Long story short, I think Holmes knows what he's doing, even if we don't. Despite his emotional detachment, he really is tuned to the mental state of others, and he knows what's best for each situation. Because he isn't connected with the police officially, he's in a unique situation to do the better thing, even if that means circumventing the law. The fact that he sometimes lets the perpetrators go only increases my respect for him.