Blackberry Z10 without a doubt, best phone ive owned and thats me coming from a GS3 and an iphone4 in the past.
One thing the Z10 proves is that its not all about hardware specs

, its the user interface which i find after a week of owning still amazing. Sure theres a bit of lag in the settings menu that i find but thats due to the fact that the settings was made with adobe air...which doesnt make any sense but hopefully future updates will fix that bit of lag.
Compared to my GS3 which was rooted and now is at stock, the Z10 absolutely flies. Finding my GS3 lags quite a bit, probably due to touchwiz being a stinking pile of crap.
Only thing that is lacking with the Z10 i find is the apps but every day more apps are coming out and the apps i cant get on the Z10, i can just sideload the android version to my Z10. So really im not missing any apps that much.
But all in all the Z10 is the one i would pick each and every time and thats nothing to do with me being a Blackberry fanboi

. Android no longer interests me in the slightest although having played with the new HTC One i do like it but purely from looks wise. Dont get me wrong, its a nice phone hardware wise but its HTC sadly and i wont ever touch another HTC phone.
As for the iphone5??, seen it, played with one and i find it fugly as hell, its not a very nice phone to hold in the hand compared to the Z10 or even the GS3...unless you have it in a case. But more importantly its probably the most boring OS i have come across. Apps wise its head and shoulders above everything else although Android is pretty close. But seeing as im not a huge app whore, it doesnt interest me in the slightest.