Which SPF is the best SPF? THE ONE YOU WEAR.
I can't wear most sunscreens and sunblocks. I can actually wear this sunblock without the skin on my face completely freaking out, going red and blotchy, turning hot to the touch, itching and reacting like mad. If all else fails you, give this a try.
AS WITH ALL SUN PROTECTION: Let it sink in thoroughly (at least 15 minutes) before applying cosmetics and it makes a lovely primer and SPF in one. Never, ever dilute any SPF product with oils, moisturizer, cosmetics, water or any other product as this cuts its effectiveness, leaving you unprotected.
Don't forget to reapply as needed.