Dremora Valynaz (Level 46) are much stronger than the Dremora Lords (Level 27) summoned with the conjure dremora lord spell.
I have only the necromancy side perks of the conjuration tree, twin souls (2 summons), dark souls (100 hp buff for reanimated dead), necromancy (greater duration, irrelevant for dead thrall).
The forsworn ravagers are wearing the following equipment which I upgraded (100 smithing with 4 pieces of +25% smithing gear) and enchanted (100 enchanting with middle enchanting path maxed):
Armor:
- Forsworn Headdress (Legendary) with +40% archery damage
- Forsworn Armor (Legendary) with +62 health and +25 light armor skill
- Forsworn Gauntlets (Legendary) +40% one-handed damage and +40% archery damage
- Forsworn Boots (Legendary) +40% one-handed damage and +37% frost resist
- Forsworn Bow (Legendary) 20 absorb health, chance to paralyze for 5 seconds
- Forsworn Sword (Legendary) 20 absorb health, chance to paralyze for 5 seconds
- Staff of the Storm Atronach
NOTE: Forsworn are the only thralls that will use any FORSWORN armor given to them. That means you can enchant and upgrade any forsworn armor, remove the armor originally on the corpse and replace it with upgraded and enchanted forsworn armor you got from other forsworn and they will equip it once you fast travel to any other cell (location).
The game difficulty was set to master.
The results?
Here's the video: http://youtu.be/YM7T77iqkjs
My thralls wiped the floor with the Dremora Valynaz unscathed.
Conclusion:
The dead thrall spell can be vastly superior to the conjure dremora lord spell if you are willing to put a little effort into it.
The conjure dremora lord spell isn't bad however. They can be summoned on command and is good for people who don't want/enjoy crafting skills. I personally enjoy crafting.
I'm just tired of the people saying the dead thrall spell is garbage and possibly turning people away who would actually enjoy using thralls.