I believe he thought Ai was comparing "cache" values in these devices. The problem though, is that your definition doesn't apply either, even though it's clearly what the writer meant to convey. What the (Ai) writer really wanted to say is "elicits stronger reactions", apparently. Also, "cachet" is a french word ;) and it really means "that has class". Obviously, the iPhone has more class than the GSn, with n being whatever integer you want.