I go harness magicka all the way. The extra shield strength from dampen is nice, but to me the extra shield strength seems unnecessary for the majority of the content in the game and I would rather have a little more towards sustain that harness provides.

Speaking from PvP perspective, dampen.

For harness to be fully effective, you have to be hit 3 times. From my experience, it simply does not last that long - it is usually removed by a single frag (and then some). On top of that, the attack has to be magical, and half the time you'd be hit by physical/poison attacks instead.

On the other hand, the dampen morph is always fully effective.

Ultimately which is better depends on your build tho. If you absolutely need every scrap of extra magicka to function, go with harness.
Also, if you are not wearing any(or too few) light armor pieces, go with harness (since its bonus still works while dampen one is useless)

WhiteMage wrote: »

Without CP, the choice is obvious.

That would depend on your build. For example, im currently running a mDK light armor build that is centered around heavy fire staff attacks with igneous weapons. The main source of damage is free and actually restores magicka to be used on shields/wings and such. The build works in azura just as well as in TF.

Harness most of the time for pve, it allow you to spam it in certain circumstance. I even use it in order to refund my magicka (against lord Warden for example, these bubbles give me my magicka back with a bonus when I shield them).