Well prio for MM is agi then mastery > crit > haste > versa. Mastery increase your range and damage of all your abilities. You can shot at enemies from 56 yards if u have all mastery gear which is pretty crazy.
I haven't played BM much since they removed Bestial Wrath from 20s so can't really tell what would be the best.
Good thread about mastery across all classes and specs by @Bop