Actually the name of the monster/demon/creature suggests the number of tails it has. Gaara's monster, Ichibi [sp?] has only one tail, and Kyuubii has nine taails. Every demon is an immense collection of Chakra and every single one of them possesses a lot of destructive force and different capabilities.
Remember, there are 9 and scattered accross the world. Sand's demon was Icibi and hence was locked in Gaara. Fire's was Kyuubii and was locked inside Naruto.
Every nation had different demon, whith different capabilities etc... and their power is beyond human comprehension so humans have no idea how to control it even though they have tried over the years to collect their power and use it to make it as weapon- without succeeding.
So you cannot be specific yet ^_^