Because UV rays are nothing to mess around with, we went straight to the source, and asked dermatologists and skin-care experts to clarify once and for all. The verdict? It's a toss-up. Every single pro we spoke to agreed that the ultimate deciding factor is personal preference. "The most effective sunscreen is one that you'll use every day," says medical doctor-turned-beauty entrepreneur Lamees Hamdan, Founder and CEO of Shiffa . "That's why I say choose the texture that most suits you."