Some swear by it, some swear at it. You pays your money and you takes your choice.

Do you mean cooked brisket? If Sony mother makes a brisket and freezes leftover about once a month. I get the frozen leftover and keep them for weeks until I defrost them and they're always delicious. Best bet is to let it thawslowly over a day or two in the fridge but once that's done and reheated its as delicious as the day it's made.

I have had no problems with freezing brisket, cooked or not.

You can cook your brisked from frozen or not, however is most convenient. You can freeze your cooked brisket, and reheat it from frozen or thawed, whichever works best for you. However, if you are going to freeze your cooked brisket, I recommend cooling it thoroughly first (like several hours to overnight in the fridge) so you can remove all the fat that will coagulate on top when it's cold -- BEFORE you freeze it. Brisket always seems to turn out wonderful, no matter what you do!