Of course I'm an amuture but my Boston butt is killer and I honestly believe I could get in the winners bracket. If not I could sure have fun and learn something.
By the same token, the more different samples, the more chances to not impress a judge as well. Good brisket slices, but if your burnt ends aren't fully rendered out will cost you. Good chunks of pork, but overdone money muscle, will kill you as well.
Bruno is spot on about your entry. Butt has an advantage over ribs and chicken because if you put cubes, slices, and pulled in a box the judges are obliged to take a portion of each as an example of your box. That give you three chances to impress vs one bite.
Brisket often comes with slices and burnt ends so it also gets a couple chances as well.