Typing:
Vaporeon resists common offensive types Ice and Fire, and, in this generation, Steel. Weak to common offensive type Electric, but also weak to the uncommon Grass. Immune to Water, another commonly found offensive attack, allowing it to easily switch into any water type and regenerate health with Water Absorb.
Sylveon resists the very common Fighting type, but it's other two resists are uncommmon; Bug and Dark. Weak to the a threat made more common in this generation, Steel, but it's other weakness is much more uncommon; poison. Immune to the powerful Dragon type, allowing it to easily switch in to an Outrage, but it should be noted that some popular dragons, like Garchomp, carry Poison Jab to deal with this threat.
