I've had broken promise since our first 4h kill on 11/30. We have had 5(FIVE!) last laughs drop since then and I have had the unfortunate luck of not being there on any of the 5 kills where we got him(I work and miss the first two hours of each of our weekday raids!). Our dks have last laughs for offspec tanking.
Also the one time I was there for it, we gave it to the paladin because, "Paladins SoR scales off weapon dmg." And I am the only orc in the guild, damn it.
My impressions of using the BP is that its almost a non-issue. I am such a good tank that it really doesn't matter if I'm using something w/20dps less and .9s faster.
Of course it would be better to have it, but without it, you are not going to suffer.
Hmm i cant really decide Broken Promise or my Red Sword of Courage... People keep saying that Red sword is best due to its speed.. I was thinking Red Sword on trash and Broken Promise on Bosses but i dunno