It depends on what your role is and what you want the shield to do. Are you a DPS that just needs a little damage mitigation and finds the Fragmented morph's ability to also deal a little damage appealing? Or would you prefer a larger shield that also buffs your healing for those "Oh, *Bleep*!" moments?

If you're a Tank, then hands-down go for Igneous. Even if you're a DPS, Igneous is hard to pass up, especially if you also have Dragon Blood slotted on your bar. Igneous and Dragon Blood, plus the healing passives from the Draconic Power tree, are an excellent combination that should really up your survivability in any case. I personally have never used Fragmented, so I can't comment on its effectiveness or whether the added damage effect is worth it.