Very interesting, appreciate the insights. Any idea which sensors/brands have good sensors & matchers? I'm perfectly happy to pay a bit more for a nicer device if I knew which ones were legitimately better, just never been quite sure how to actually figure that out. I'm also a cynic and don't trust review sites or anyone trying to make a sale, of course the review site I just found lists them all as "reliable". As far as updating the image, I wondered that too. Could you effectively trick the sensor into morphing the stored data into another fingerprint. Just seemed like that'd be the most straightforward way to keep it reliable over time.

ohhh, maybe you know the answer to some finger-print reader questions I've had for awhile. Got a Kensington USB reader for my Desktop to login with my fingerprint. Works great the moment after I train it, then generally gets less reliable over a week or so, quicker if I've been doing any manual labor. I can of course re-add my fingers, but I'm curious what the difference is between it, and the sensor in my iPhone which is much more reliable over time? Is the iPhone revising it's stored version of my fingerprint? Or maybe just generally less picky?