You are all right, BBQ brisket (or it's close relations, salt beef and pastrami) are amazing wen done right, but bloody horrible when done wrong.
To cook a brisket, BBQ style, you need:
A large pieve of brisket (don't try it with a small bit, it just won't work as it dries out too quickly), it needs to be as evenly thick as possible and have the fat trimmed to about 1/4inch.
A BBQ rub (part of the fun is making your own, so do so, adding more of stuff you like, less of what you don't)
A charcoal BBQ that you can control the heat on, or a hot smoker.
A temperature gauge for above
A meat thermometer.
Method
Take the brisket and rub all over, generously, with the rub.
Place in the fridge overnight
Light up the smoker or BBQ
Get it to 180F - 200F
Leave it alone, only adding more fuel if the temp drops, for 5-6 hours, or until the internal temp reads 195-200F
Once it has reached that temp, it is still not ready! Remove it from the grill and wrap it in foil, then several towels and drop it into a cooler box to rest for an hour or so (it will keep warm like this for about 3 hours).
Serve.