The Dermatone paste I use is only spf 15, but it is a physical block which has some definite advantages.
It's my "uh-oh" or extra back-up block. Usually I wear Hawaiian Tropic or Banana Boat kids' sunscreens (low irritant levels, mix of physical and chemical blocks). I can put paste over my usual sunscreen for a little extra physical boost, or just wear the paste alone if I forget the sunscreen. If you smear the paste on REALLY thick, it is more than spf 15. Works ok on lips, too.
The paste is very handy, nice sized little tin, and no worry about spilling.
"If Americans want to live the American Dream, they should go to Denmark." - Richard Wilkinson