Phone Buff's Speed Test; iPhone 5S vs Nexus 5
This really shows how fast the iPhone 5S is.
And what's interesting is that Android fans say they iPhone can't truly multi task yet, the stopwatch app was running perfectly on the iphone in the background where as on the Nexus 5, it stopped the background process.
This maybe the best "speedtest" I've seen as it shows how fast you can accomplish multi things on each device and iPhone 5S was the clear winner ever after getting a slow start.
Nexus 5 vs. iPhone 5S Speed Test (via PhoneBuff)