The really encouraging thing imo is that the Royals have earned their 6-3 record in such a variety of ways. They've won slugfests, come from behind, held onto large and small leads that they built early, won and lost pitching duels, etc. It is a small sample size, but if you look at the schedule and teams they have played their record is what you would expect from a playoff contender they have played .500 ball against the better teams on the schedule and have dominated weaker competition.
I think the other key, and what makes this Royals team different, is that they are markedly less vulnerable to prolonged losing streaks as they have been in the past. The 'pen is simply too strong (even with Holland's struggles) and there is simply to many starters in the rotation capable of winning a pitching-duel to warrant fear of a bad streak.
