At the competition I participated in a couple of weeks ago, there were 2 similar to the PBC's.
The one was a homemade version - complete with metal piping for venting! I did not get a good look at the other unit - it was on the other side of the area. The first was next door to us and the guy running it was pretty stoked about it.
As for results, he did ok. Middle of the pack (8-12th place) for all 3 categories, but I cannot remember what he cooked on it as he had a couple of different pieces in use.
From what I saw, it is not always the equipment but the person using it and what they do with the sauce. There are so many variables to the competition, it is hard to pin a win on a specific piece of equipment. They have an advantage with the larger units but , from what I saw, it is because they can cook more food and be picky about what they send to the judges.