as you are looking at top of the range, that pretty much leaves you with th galaxy S4, HTC one X, or Iphone 5S... (Give or take the odd lumia if you like the windows OS, and yes some people do

)
personally i'm a galaxy fan, but the others all have huge benefits.
HTC One x - awesome screen.
Galaxy S4 - power, grunt and pretty good alrounder
Lumia (1020, i think) - 41mp camera, and to be fair, not a bad alrounder. Again, if you can enjoy the WIn OS.
Iphone 5s - simple, sowkrs... but annoyingly thin.
its more of an ecosystem thing though.
Itunes will work on i devices better, and your idock's etc. But now you can sync to android etc, and works really well.... My sgs3 talks with my tv, and controls my servers etc. so is fine for me.
so choose the eco system. (What type of device fits your current lifestyle, music, film, sat nav, physical connections)... and then choose a device after that

Good luck
