I've been using TerraSport SPF30 the past year but it is no longer sold at the store where I bought it from and it's not mainstream so I cannot find it at Target, Safeway, Walgreens, Trader Joes, etc. It seems very water resistance since sweat and water tends to bead up on my skin and takes a bit of washing to make covered areas not feel slimy. It does leave a bit of a sticky/tacky feel on my skin so that is a bit of a downer.
It worked like it should -- haven't got a sunburn with it applied yet, but I tend to tan before burning.
Suggestions for anything similar welcome, but they must be at least SPF30, otherwise they won't be covered under FSA. Additional requirements: must be sweat resistant and provide good UVA and UVB coverage. Prefer something natural like the Terrasport stuff I was using.