I don't know if there is just one answer. Brisket should not be dry; nor should it be real wet. If it is dry, it was cooked too long (or too hot)........but it may have been tough even if you pulled at 190. Some briskets are just plain mean. That's why brisket is so hard to cook to perfection and get high scores in comps.
Try again and go by temperature. But make sure you get the most flexible piece of meat available (bend the two ends of the brisket together at the store) It's a learning proces.
Gator Pit Entertainer