My previous ride was a Cayman S, my dad owns an M4 and now driving an M340ix I've spent a considerable of time owning/driving the tamer version of both these vehicles. After hours and hour in each- the biggest difference when driving is the feel in weight. The Porsche feels like a go-kart on steroids, it's nimble, agile, tiny and you push 1 sport button to set it. The m4 and m340ix have the weight of a car and configuration settings of a cockpit. They're both awesome but in very different ways, and the thing not mentioned in any "porsche vs. x" reviews is this- if you own a Porsche, you NEED another car. Even as a single guy with no kids, the impracticality is off the charts in a Porsche.
I'm short- the Porsche is the high maintenance woman that drives you crazy, the M is the one you marry
