I always reheat BBQ using the "boilin' bag" method. I learned a long time ago to only simmer though. I've been reheating this way for some years now, and only twice have I had a bag pop on me. Both times were when I had allowed the water to go to a full boil instead of a light simmer. Now I put my package in the water when I first put the pot on the stove, allowing the meat temp to rise along with the water. I do this for the pulled pork at our October Senior-Q when we feed 150 seniors. We cook everything else onsite, but I do the pork ahead of time and do the "boilin' bag" thing in the DPP's onboard turkey fryer. I TRY to let it thaw first, but have frequently taken something out of the freezer and gone straight to the pot with it. The flatter the package, the better this works from the frozen state. A whole brisket flat will go from frozen to hot and edible in about 30 minutes, for example, while ribs will heat faster than that.
When I'm cooking up a big batch for the freezer or for other people, I always do the ice bath to chill quickly. I let the meat cool just a bit, package it up with a bit of sauce/juice, vac it, and throw the vacuumed packages down into an ice-water slurry in an ice chest. It chills them down much quicker than setting them into the fridge or even the freezer, as the warm meat will heat up the refrigerator before it cools the meat. After at least a few hours in the ice/water (adding ice occasionally as it melts - I usually go through 3 bags of ice in this process), I dry the packages, and it's off to the freezer or the refrigerator. This is the fastest chill-down method I've found short of a nitrogen blast...
Keri C