I believe my Xperia Z will replace the need of my two phones. I usually have one big screen smartphone (Lumia 920) and one tough phone (Motorola Defy).
Now I will be taking my Xperia Z at work, beach, pool, running, fishing, watching movie and play chess online! (I am tired of waiting chess.com releasing app for windows phone). I do however miss superb battery life with Lumia / Windows phone OS.
To those who have trouble with their Lumia 920, I felt sorry. My first lumia does have trouble with the camera but the replacement one has no issue whatsoever. Maybe next Lumia should be waterproof and I will be back with windows phone! Innovation is really important for mobile phone manufacturer. So much competition!