Phone advice

[ChoccyJules]

My iPhone 4s is dying quickly. I don't want one of those huge phones and really don't like them weighing my bag down (I tend to have small crossbody bags so the phone makes a difference) so I'm looking for something around the 140 g weight.
Considering Samsung A3 or Sony z5 compact. Anyone have any experience of either? I see there's a new A3 out next month but it will be pricier.
I also wonder whether I am limiting myself and could get used to a slightly bigger screen.. Especially as the eyesight changes!