Some thing that I look for is that a dog goes in and catches hard, but is under control. Its just my opinion that if a dog goes in under control they get a better initial grip, which should cut back on them needing to re-grip. It also tends to cut back on dog injuries.
Although I like watching those catch dogs that hit so hard the hog and dog both go rolling
, its not my preference to own.
I agree with Mike that more dogs do it than most people think. It just has to happen some times.