If you wanna fast, prompt and have every single update, than You buy Nexus.
I wanna have Sony and dont mind about updates. Xperia Z is still very powerfull device and it will have developers and we shall have many Android L roms.
Sent from my Sony Xperia Z C6603 using Tapatalk
GSM: SONY Xperia Z C6603 --- JIAYU JY-G4C
ROM: Android Kit Kat v4.4.2 / build 10.5.A.0.230 Denmark "3" / stock --- Android Jelly Bean v4.2.2 / 20140401-115458 / rooted
LCD: 5" Sharp 1920x1080 TFT LCD / Dragontrail --- 4,7" LG 1280x720 IPS LCD / Corning Gorilla Glass
MSD: SAMSUNG Pro 16GB MicroSDHC Class 10 FAT32 --- KINGSTON 8GB MicroSDHC Class 10 FAT32