ON sun cream I highly recommend P20. (they do factor 10,20 and 30 versions but P20 is the brand as its the original)
It looks expensive, but its genuinely only applied once a day. I used to burn like hell but that stuff stand up to strong sun for me and I do not burn at all.
I recommended it to an Italian work collegue who bought some as she burned a lot and holidayed in Scicilly annually, she came back raving about it, her family were all trying to steal if off her.
Its a little bit of a pain to apply if your a little hairly (unlike Ace) as its more oily, but once soaked in you don't know its there and no need to reapply all day, so if your outside for the day, even if not bright sun its worth putting on.