Yea i use various forms of cloud spells because it only takes 10 magic and you can use them. And they dont stack with magic so any build can use them.
I have found that yes most enemies are capable of being poisoned. I know of man eater, old hero, flame lurker to name a few.
Acid cloud is only good for pvp as it does nothing in pve. However that being said it is not useless. Its funny to see most players stop in their tracks and run away. Its very handy if you need a few extra seconds to heal or spice it up.
Death cloud does not seem to work on most boss characters. Lol the phalanx does and its fun to cast and walk away.
Death cloud again i believe is more useful in pvp. Because of the stamina penalty it has on the enemy.
So if you are mainly going for pvp acid cloud and death cloud are the way to go.
If your are pve mostly then id say poison cloud.
