Better defensively than Orr.Best defensively of the Big 3.See the 1969 Conn Smythe win before the two broken legs. Also evidenced by the success Team Canada had when he played in the 1972 Summit Series on International sized ice. Plus the Bruins with/without Orr could never apply constant offensive pressure against the Canadiens with Savard. Could play physical or finesse as situations dictated, on international, regulation or small rinks.
http://www.youtube.com/watch?v=l22FV4105p8
The difference between Serge Savard and Bobby Orr defensively is small but important.
Serge Savard was equally effective on RD and LD, similar to Doug Harvey. This allowed him to match-up defensively against a team's and a line's strength, be it RW or LW. Orr playing mainly RD was not used in the same fashion.
The other difference is one of defensive style. Bobby Orr was spectacular defensively - ragging the puck on the PK, blocking shots and transitioning to a dangerous rush. Serge Savard was simply efficient. Ice the puck on the PK,allow teammates to rest or change. Save energy for ES. Take away the shot and transition to an odd man rush - evidenced in the video above.