I think there is a big difference between feral hogs and feral/wild boar. I believe the hogs have much higher birth rates because of the commercial genetics somewhere along the line, and so spread much more rapidly. Am I right that alot are wild boar/commercial pig hybrids?
They all do huge damage to pasture, crops and fences, etc. but IMHO if an area is going to get them, you want to hope for pure wild boar.