"Best defense" in this case is a reference to a combination of depth and quality throughout the defensive corps. Nashville and St Louis have a slight edge in this regard given both have outstanding top 3 defensemen. The fact of the matter is the Rangers defense does not get scored on "so much", two bad games hardly forms a pattern nor is it indicative of the quality of the players. Yandle is a great defenseman, he's adjusting to a new team, coach, system and put forth some good play last night. +/- is meaningless and is completely disregarded by nearly every person with the slightest interest in the statistical analysis aspect of the sport. Goals against can happen for a plethora of reasons, not even necessarily the fault of any individual on the ice (e.g. a lucky bounce) never mind a specific player. +/- can also vary wildly in the span of a few games and a small sample size (such as two games or even the entire playoffs) completely throws the numbers off. Also a player deployed solely in the defensive zone will not have a good +/-, but perhaps he is only deployed their because he is a fantastic defensive player. These are just two examples of why it's a useless statistic. If you care for more you simply have to use Google, there are many articles which go into the intricate detail as to why +/- has been utterly abandoned. CORSI and FENWICK are much better indicators to quality of play both in a singular game and over the course of a season. However, defense is hardly quantifiable and a large part of hockey analysis for defense is subjective in nature. The defense is not only considered good because of the goalies, at the very least Boyle, Yandle, and Klein were all considered to be good before they came to the Rangers. Girardi I'll grant you is overrated, but McDonagh and Staal are both excellent defenders. This is a defensive corps that allows very few shots, forces most to the outside regularly, and is respected for a reason.