Though platinum and white gold may look very similar in high polished finished pieces, these precious metals both have their own pros and cons when it comes to jewelry.
Platinum is a stronger metal compared to gold, it is also used in a purer form. You might be surprised to hear that platinum scratches easier than gold even though it's harder, however the metal is simply displaced rather than worn off. White gold is more brittle and when polished or scratched small particles are removed. Platinum is grey/silver in natural color and will not turn yellow but develops a platina quite quickly which platinum lovers can appreciate while some do not enjoy the dull look and prefer the high polished with rhodium finish. Though white gold does not scratch as easily, it will require rhodium plating every 6 months to a year to keep the silver color.
Platinum is a heavier, denser metal and though is is stronger and more durable, the purity of the metal can leave a thinner made piece softer and vulnerable. Platinum is more difficult to work on for jewelers, requiring a higher heat.
Platinum is best to use as a head to hold a diamond as it will absorb impact and protect your diamond better and will never turn yellowish as white gold does. For thinner rings, white gold is better as it will maintain it's shape better. If you prefer a high polish look, white gold is a better choice. If you prefer a heavier feel, platinum will add weight but if looking for something lighter weight such as earrings, white gold is ideal.