I have nothing against you, in fact I am just trying to help you. But your question comes off as though you are being unreasonable.
"slop job" does just not cut it and you probably used those terms or worse with the builder. Treat the guy with a little respect and talk with him about your concerns.
What you need to do is pick an item that he is doing sub-par work on. Take a few pictures of it and call around to find out if indeed he is doing it wrong. If he is just not a perfectionist and you are then you are not going to win anything. I have this same problem, and am learning that not only can no one do perfect work but neither can I!
Go out and find other projects that are being done how you think is correct. Then bring both sets along with any opinions of other pros along with you to talk to the ubuilder. Arrange a meeting don't just accost him on a job site.
Tell him that you are concerned and here is why. Lay out your argument. Let him tell you why he is doing it differently. He will likely even point you to other houses he built the same way, go check them out and see if the end product is really a problem.
In the end you will either convince him or you wont to do something a little different. If you don't with being pleasant the go talk to a lawyer if you have to. It will cost you a lot more if you decide to go to court, and I am not talking only about the fees. It is worth avoiding if you can.