Martin was passive on defense. The Bruins are aggressive on defense.
Sure they are clogging up the neutral zone but after that, nothing at all similar.
A defensive system always looks better when you have bigger aggressive players. Your defensive coverage will eventually crack when your players are Cammalleri, Gionta, Gomez, Plekanec, Kost, Kovalev. On the back, we were a lot less mobile than Boston too. Gill, Hammer, Spacek, were all slow and a lot less mobile, not to mention old, than what Boston have. Markov was unfortunately almost never present under Martin. PK was our only bright star.
But essentially, like the Bruins, we focused on collapsing in front of our net, blocking passing lanes, keeping shots on the perimeter, and having a fast counter attack.
Boston just have the right players to play that system, and they've had time to perfect it over the years.