I "upgraded" from the Sony Z1 to a smaller phone - the Z5 Compact with a 4.6-inch screen. I was seriously mulling the iPhone 5c, but Virgin made the decision for me and discontinued it. There's something fantastic about only having to use one hand with a phone and it fits into my top pocket - a life saver at work (IT in a school). It has the power unlike every other smaller phone and up-to-date features like a fingerprint scanner. Optus 4G Plus is so fast (why does Armidale have 4G Plus but not the Sunshine Coast in Qld where I live?). People say the phone is thick but it has never struck me as a thick phone.
It's a great phone and I will have it for several years, no upgrades because the new phones are gigantic and they won't be any better in 2 years, everyone knows it. (There's now the even smaller Z6 Mini out soon, but I'm not sure about its 4-inch screen. It's probably too small)