Xpiera Z showed poor results because it has a 1080p screen and same SoC as Nexus 4. In other words, Xperia Z has to render at a resolution of 1920x1080, while SP, N4 will only rendering at 720p. Pretty waste of a phone. I still don't understand what convinced Sony to release a 1080p phone with a S4 pro. While HTC and Samsung were releasing their phones with much powerful SoC.
So is SP is better than Z?