If you want to avoid all spoilers, I reccomend siding with Galahad. You get magic items and a more reasonable narrative motivation. Don’t read further.

Galahad

If you side with Galahad, exposing and killing the traitorous Captain and Chieftan One Eye, then Fearghas our favourite levelheaded Quartermaster will be made the new Captain and Cillian our favourite psychopathic Bounty Overseer is made the new Quartermaster.

I consider this the better outcome. If youve done all the quests around the keep, then you know Fearghas is a good leader. He’s kind and practical, while also being strict when needed. Everyone mostly respects him and he genuinely just wants to do a good job and keep his people alive and happy.
He will retain Kamelots support and Galahad respects him. Galahad is far more brutal and strict. But he is not mad, he has good reasons for his brutality and a solid plan for the future. Though i don’t agree with his methods, he is the lesser of the two evils.

Side with Galahad

Nets you the following loot (make sure you loot the corpses of notable enemies/characters):

1. Ulf’rs Stomrforged Cape: +5% HP
2. Volkers Beserker Totem: 20% crit chance +25% damage taken
3. Breadans guantlets: +2 stamina
4. Breandans Cape: +20 HP
5. Raiders Skirt: 20% damage
6. Generic Knights Breastplate: recover stam 33% faster after overexerting yourself. 1 per Galahads Squire.

Siding with Galahad by far results in the better loot. The actual fight is reasonably easy. Two dozen beserkers are defending the temple. But you have the aid of Galahads archers and Squires (who you can also loot when they inevitably die). You can lure the zerkers down the stairs to fight them one or 2 at a time.

Siding with the Traitors

This results in the traitors trying to establish the region as an independant nation at war with Kamelot. They are pinning victory entirley on the hope that every other faction will turn on Kamelot after finding out about a controversial secret about arthur and the original knights.
The player isn’t really given a good reason to side with the traitor captain, other than being promised to be told the secret (which you find out anyway).

The loot you get siding with the traitors:

1. Galahads Mace: inflicts 70 burn on hit(status build up, not damage, this is weak). Two handed mace (49-59 base dmg)
2. Generic Knights Breastplate: recover stam 33% faster after overexerting yourself. 1 per Galahads Squire
3. Great Beasts Bone: +5% hp

Unless you really like the look of Galahads armor theirs no real reason to choose this route. The game seems to hint at this, as the dilogues with the captain are really underdeveloped and you arn’t given any narrative reason to side with him.
Even if your attached to the warriors in the camp. They are content to mindlessly do whatever One Eye says and are actively seeking “glorious” death in battle.