The 5s fingerprint access is so much more convenient than a pin code!! I've never counted how many times I enter a pin code on my mobile, but it's a lot. And having finger print access whilst still using a device with pin access is reinforcing just how handy fingerprint access is.
I used an iPhone 5 for several weeks and this is a totally different experience due to the convenience of the fingerprint access.
Around 2003 I used finger print recognition on the HP iPaq ODA (made by htc). It was a bit hit and miss- the 5s implementation is great, in part because it's built into the home key and you can use different fingers, depending on how you pick it up. Ideally, I'd like to be able to specify which apps don't need any id; which need fingerprint and any that night also need a pin code as well as fingerprint (eg eBay, or others that spend money).
There are apps on android that allow restricted access to selected apps, and the LG Flex supports a guest mode, the HTC a kids mode (not very good implementation) and things like the Nook tablet allow you to have multiple accounts on an android device (like Windows) - things are improving in terms of convenience and security!
For ease of access and convenience it's hard to beat the iPhone 5s. For heavier duty creation the g flex is great (despite it not having the sharpest screen)- now if only it had decent fingerprint access...
And if only the iPhone had the double tap and non shuffle on/off key (the iPhone 4s was better in that respect, as is LG's approach of having the on/off button where my index finger naturally rests when I pick you the phone!).