Size isn't everything, as I keep being told...
I'm a fanboi with a full complement of fruity gizmos. But I really don't need or want a bigger iPhone.
When I lent my girlfriend one of my 5s (I have three in use) after she let hers go for a swim down the pan on holiday, I put my SIM into one of the old Nokias* I have in the garage and used that for a few days. I'd forgotten how nice it is to have such an easily pocketable phone with days of battery life.
As for the latest knocking Samsung advert, well that is simply stupid but probably so apt for the 'bigger is better' eejits. My girlfriend also has an old S3 which is horribly plasticky and cheap looking and has to go in a bag, realistically. Given my suits and jeans don't have clown pockets and I'm not metrosexual enough to carry a manbag, I'll pass on the 6S (and the Samsungs) thanks.
*My spare spare fourth phone with a live SIM is a lovely small Sony W595