Pepsi Max all the way for me. Not a fan of Coke at all, but funny thing, looking at the ingredients for Coke Zero and Diet Coke (Coke's sugar free equivalents of Pepsi's Pepsi Max), they seemed to be pretty much exactly the same, yet Coke Zero seems a lot sweeter, and thus nicer, to me. My very rough, and to be taken jokingly/with a grain of salt, theory on that is that it's deliberate to play into people's expectations about diet products; ie nobody trusts 'diet' products that taste too good... I know I don't 
Whereas Coke Zero doesn't claim to be anything to do with dieting, just sugar free, and thus still aiming to taste good. Basically Coke Zero is much closer to Pepsi Max to me, than Diet Coke, so if there was absolutely no other option I would reluctantly accept Coke Zero as a substitute, but not Diet Coke... that stuff's horrible and I'd rather drink water
Whereas Coke Zero doesn't claim to be anything to do with dieting, just sugar free, and thus still aiming to taste good. Basically Coke Zero is much closer to Pepsi Max to me, than Diet Coke, so if there was absolutely no other option I would reluctantly accept Coke Zero as a substitute, but not Diet Coke... that stuff's horrible and I'd rather drink water
