This is only my opinion:
I took the judging class several years ago and helped with two in the following years.My class lasted from 9am to 1 pm. There were a lot of people in each class. Some of the people I have seen since; at competitions, others I have not.
The food in the classes was cooked by competition cooks, two pretty frequent competitors who do well on the circuit. The food was started the night before and finished similar to competition times: they did chicken at 1000, ribs at 1130, pork at noon, brisket at 1200. (they were an hour less than competition).
The one problem I saw was not many questions were answered between meats. If a question like "what did you think of the chicken? was I right to judge an 8-7-7 or should it be another score? The answer I got was "in my opinion..." And so it went with each meat. The general class discussed (lectured about the rules) and spent a lot of time on garnishes (this was a few years ago) and sauce pooling. Not much on taste, a little on tenderness, and appearance.
Generally, you learn more by asking cooks after a competition. You NEED the course in many cases, to get to judge. There are great bunch of brothers on this board that would be more than happy to discuss food after judging is done or at a regional meeting and such.
I have cooked many foods and judged many foods prior to doing kCBS judging. I worked professionally as a chef in a small restaurant but need more gainful employment (not much pay there!)
I took the class thinking it would help me be a better cook and, as was said previously, it did not. What did help was going to competitions and tasting food. In the judges tent and perhaps, if you get lucky, a brethren may offer you some good BBQ to try and know that is what really got me hooked on wanting to cook BBQ.
The main issue I have is, that my area is saturated with judges. I apply for 10-12 contests a year, and I get to judge 2-3, on a good year. I travel up to 4 hours away to judge a competition at this point.
And remember, it does cost money to judge, travel expenses (gas wear and tear, hotel room/campground, meals other than BBQ, keeping your membership, etc). It does not cost as much as cooks pay out, but it isn't free either.
I look at judging as an honor, I try to do the best I can and do it fairly. It costs a lot of money for cooks to compete and they deserve a fair shake. Oh, I also do not take left overs home as I feel it is disrespectful, but that is me.
Have a good time, meet some good people and do the right thing!