Question about some Evoker skills (help needed)

Hi !

I'm playing single player with an Evoker. Currently I'm level 22, and I need help in determining the helpfullness of a few Elemental skills.

#1: Tempest (2nd skill in the Lightning tree): The Evoker creates a dark cloud of doom which fire at all those foolish enough to remain nearby.

How good is that skill ? I need all the things you can think of about it.

(remember that I'm playing Single Player). I already have the prerequisite skill (3 ranks of Lightning field).

#2: Arc Legion (3rd skill in the Lightning tree, requires lvl 30): Channeling the elements of Lighning, the Evoker emits several electrical arcs through a Focus device. While focused on enemies, costs 33 Power per second.

Same question as above.

And finally,

#3: Hellfire (3rd skill in the Fire tree, requires lvl 30): The Evoker calls upon the very flames of the Underworld to immolate enemies.

Your comments on usefulness and other things about these skills would be greatly appreciated.

Thanks for your replies !|||Anyone ? Please ?|||Well i can at least comment on the effectiveness of tempest, i've got a level 26 evoker right now that uses tempest, field of lightning and spectral lash, and i have to say tempest got a huge improvement with patch 1. It used to not work if their was a short ceiling, but that was fixed and it has a much larger range than it originally did. Its definitely been worth the few points i have in it so far, and if you want to focus on lightning you'd need at least a few in it anyway.