This guide uses information from the Prima official strategy guide to explain how powerful main abilities are compared to sub abilities; how abilities get weaker as they stack, as well as stacking restrictions implemented to some abilities; how the brand affects the sub abilities you can get on an item; and a few more related points along the way!
Key times:
1:10 - Sub vs main abilities
1:36 - Stacking abilities
3:15 - Abilities stacking restrictions
4:28 - Item unique effects
4:52 - Brand affect on sub abilities
5:50 - Changing or adding an item's abilities
6:24 - Perks mixed with cosmetics - good or bad?