I have exactly the same choice (ie a pair of both these tyre models) and the next tyre replacement will be a GP4S till after Easter. It's a real pain to mend a puncture when it's cold (and maybe wet) and a GP4S is more robust. The 5000 offers significant rolling resistance advantage for long summer rides.
But may I add some data in here. GP4Ss come up narrow, ime. The 5000 comes up on spec (for my rims and pressure).