You almost have to try both and see which one works best for you.
Sunsleeves do OK for me up to mid-80s at home, perhaps 90F or so in low humidity (<25%). I've never had problems with sweat evaporating over sunscreen, except of course when it's so humid nothing evaporates, period. (Bullfrog get is my favorite; works well and can be applied over moderate sweat.) So if I'm out west in spring or fall, I may take the sunsleeves, but I'll also take sunscreen in case it gets too hot.
And to reiterate, YMMV.