Good question!
Depends on the region: For instance, a trophy in pulled pork probably wouldn't carry as much weight in SoCal as a trophy in the other three KCBS cats because it just isn't a pp area.
Depends on the level of competition: If there aren't a lot of people doing pulled pork well, there's an available niche.
Depends on what sells in the local restaurants: Just a different way of making the first point. But if everyone loves ribs than a ribs trophy will make you look pretty good. Besides, you're not really asking about the competition, you're asking about the do-re-mi. I'd guess that area sales are more ribs (beef and pork) and chicken than pork and brisket, and I'd work my competition strategy accordingly.
Bottom line... I'd shoot at ribs and chicken. But that's here. If I lived in Lincoln Nebraska I might be going after brisket.
Competitions and catering don't necessarily have a 1 : 1 correspondence. Recipes which do well in competition are not necessarily "public" favorites. It's been my experience that judges are actually more conservative than the general public. Certain categories are especially sensitive to materials choices -- brisket most of all. It's my expereince that consistently successful teams in big comps use boutique suppliers of very high quality meats. That's something you can rarely afford in catering. Something you can do both in catering and comp, is to use freshly killed (not too freshly -- you want them dead long enough to be out of rigor -- about 8 hours), local poultry. It makes a difference.
Another difference to be aware of is that judges try to consider sauce as little as possible, and rightly so. To a large extent that's true about most of us, too. The more experience we have cooking 'q, the more attuned we are to the nuances of the meats, and the more we prize techniques which enhance and bring out the meats' natural flavors. But cooking for the public is all 'bout the sauce. Like it or don't.
Consider a real effort into the "other" categories depending on what's available at your particular competitions. Sides; Sauces; "Anything But; and Desserts. A reputation in yam souffle or cheesecake or cobbler or beans or beef ribs or venison or duck breast ... isn't going to hurt you any. But a no. 1 in sauce is probably the best possible barbecue advertisement.
Rich