I find that both too wet and too dry fingertips causes recognition issues. I am on my third 5s (first was color exchange, the second bricked) and the sensor seems to work better than the first two phones. It's a pretty much seamless experience - I hardly ever have to key in my access code. I wish my iPad and various Macs had a similar feature - beats the heck out of keying in passwords.
2/28/14 at 7:28am