Bruins have been to the finals 10 times since 1970, winning 3 and losing 7.
When you think about it, considering the lock-out of 2005 cancelled the playoffs that year, the Bruins have appeared in 20% of all cup finals since 1970 (10 out of 50), and the Bruins have appeared in the finals more times than any other NHL team from 1970 to 2020.
Bruins - 10
Habs - 9
Flyers - 8
Oilers - 7
Wings/Hawks/Penguins - 6
Islanders/Devils/Stars - 5
Rangers - 4
Leafs - 0
They unfortunately don't have The Cups...
However, they've been the most consistently good/great team for 50 years, from 100/105+ point seasons to conference finals to President's trophies to Finals to making the playoffs to actual wins, win percentage, etc.
We all know the heartbreak of the playoff losses (and they sucked) but outside of the mid-90s and 2 years post lockout, this has been one of the best teams in the league in my memory and during those freezing cold pitch black February nights, I'd rather watch a very good team and I'd rather watch The Bruins in the playoffs than a Habs vs. Leafs series.