I always thought that relying on save % was very incomplete.
Look at Brodeur for example. The Devils would give up less than 20 shots on average. Their system, which Brodeur's ability to play the puck in the corners/behind the net was a huge part of, prevented the other teams from having the puck in their zone and kept everything on the perimeter. He was the best in the league at the time, yet, his save % looked pedestrian.
Luongo, on the other hand, was playing on a shitty Florida team who was bleeding shots. His save % was super high. He was a great goalie, but not better than Brodeur (as we saw in international competitions).
Boston's keepers always have high save %. I would not say that they all are world beaters. I'd argue that Boston give up a lot of perimeter shots and collapse around the net to prevent second chance opportunities. That was particularly true when Chara was in his prime. He was clearly every loose puck around his goalie.
Once again, context is king.
Penguins are a team that plays a game that leads to high-danger chances. Our goalie will never lead the league in save %, even if we had prime Hasek between the pipes.