I think people have a hard time with the 3rd use, because the 3rd use of the Law so rarely remains the 3rd use of the Law. It decays in one of two ways.
There is the 3-2 decay. This is the one that the hearer often brings about. I hear a good statement of the 3rd use of the Law. I am to love my neighbor. This is good, this is a guide for my life. But I am a sinful man, and when I hear that I am to love my neighbor (3rd), I also know and understand that I have not loved my neighbor (2nd). For the humble Christian, 3rd use will decay to 2nd.
Then there is the 3-1 decay. This occurs when people think they are using the third use, but then turn it into first use. For example - let us say we have some rules established for good order. Say the black and do the red. This could be viewed as a third use of the law - for the sake of good order, this is a good thing to do. However, once the idea of threat or punishment is added, once it becomes "you will say the black and do the red... or else" then it becomes 1st use of the Law, a curb used no longer to promote good behavior but to punish and curb wickedness.
I'm not saying that's bad. I tend to think Christians need a bit of the first use, cause my sinful flesh needs to be thumped on the nose every now and then. But it's 1st use.
Perhaps the reason the 3rd use of the law attracts such debate and confusion is because in reality... we don't use the 3rd use all that often. We might call it third, but we are really using it like 1 or 2.