Right now, the current optimal setup for endgame PvE DPS is to use all-Divines on your armor. With the typical Mundus stone of Apprentice/Warrior, this is effectively a buff to your Spell/Weapon Damage.

The alternative is to use Infused on the large armor pieces (head, chest, legs), which increases your max Magicka/Stamina.

On Live, a mix of Infused/Divines results in abilities hitting harder, but all-Divines is better for your light/heavy attacks because their scaling favors Spell/Weapon much more. On the balance, the advantage to your weaves outweigh the (smaller) advantage to how much your abilities are hitting for, which is why all-Divines is currently optimal.

But in Summerset, the scaling of light/heavy attack damage is being changed to match that of abilities. What does this mean? On a test character (Altmer magsorc with 4 sorc abilities on the front bar, Inner Light, and Bound Aegis), running Infused on the large pieces resulted in everything--abilities and staff attacks--hitting slightly harder than (by about 0.2%) all-Divines. This is with Major Sorcery active.

Does this mean that Infused/Divines is always better?
Not necessarily. The exact balance between Infused/Divines vs. all-Divines will depend on the amps available to you. For example, an Altmer nightblade will get 10% max magicka from racial passives and 8% from class passives, but an Argonian templar will get only 3% from racial and nothing from class passives. So whether or not Infused/Divines is better or all-Divines is better will depend on your build. In-combat bonuses can make a difference, too. E.g., if you have high War Horn uptime, you'll have high uptime of the 10% max magicka/stamina from War Horn and would favor Infused more. In short, I don't want to make any sort of blanket statements about Infused/Divines vs. all-Divines and would encourage that people test just how much their abilities and light/heavy attacks are hitting for.

Should I retrait my large pieces of Infused?
Assuming that Infused/Divines does perform better for your particular build (see above), the difference I observed on my magsorc test character was small enough (about 0.2%) that I don't think it would be worth the expenditure of crystals. That said, if you're gearing out a new character and deciding between crafting an Infused chestpiece or a Divines chestpiece, this is something that you might want to consider.