Ok then, I've decided how to upgrade... I bought a Samsung Galaxy S4. Found a really good deal on a used one and decided to get it.
Gave my XPS to my father so he upgraded from his god awful Xperia Arc S on ICS (a phone so slow it's literally unusable).
Honestly, I vastly prefer the interface, looks, build, and screen of the Xperia S, but the Galaxy S4 is way faster and the screen is bigger (colors are unrealistic because of OLED, I preferred the screen on the Xperia S), camera is also much better. If I was richer I would have bought a brand new Z1 though.