Are Masteries better than Synergies, or vice versa?
• Mastery: Boosts damage of all skills (not CM), full benefit of +skills • Synergies: Boost damage of 1 or 2 skills, no +skills benefit The bonuses are applied in a fashion which makes it irrelevant which is applied first. So you should go for the highest percentage boost to the skills you use most. Mastery skills gain the benefit of +skill items, which is a great help.
