I have always believed in the convenience of biometric devices. They have been hard to come by on Macs, but for many years I have used and appreciated a fingerprint scanner (infrared pad to USB) from Microsoft, that only worked on Windows, though sadly now does not work in Windows 7.
This Eikon fingerprint scanner is a USB plug in type for the Mac and comes with Windows software also. I tested and use it on both platforms, after buying from Amazon.
The product itself gets 3 stars, but the 4th star is for the fact that they made the effort to develop it for Mac, and even more so for how absolutely wonderful both the seller (reseller) and the manufacturer were to my emails about the bugs and frustrations I encountered.
It is finicky, it often takes 2-3 slides of the finger(s) or one slow very accurate swipe for it to work. Often I wonder if the 2-3 attempts are worth the hassle of using the device. On the other hand (no pun intended) it does log me in quickly when I do it "right". Using it regularly and getting used to it provide the benefit that you can ( I did) make the password far more complex/long than when just typing it in my hand. E.g. &*mYpa$$word&*43!! Instead of just &*mYpas$$ etc.
The worst thing about the design is that it is useless to plug in to a typical MacBook Pro (i5 15" for this case) when anything else is plugged in. It is too wide. So, it comes with a maybe 6" USB extension, but then it makes it even less attractive, in visual and usage sense.
Now you have loose hanging thing twisted upside down or sideways sitting on the side of your laptop (as the cables often have an inherent 'twist' torque in them that flip the device on its side), and it is now even less usable as you almost have to grab is with one, hold it up firmly enough so you can swipe a finger from the other hand through it.
Since I use external USB keyboards with my MacBook Pros, I tried to plug it into the USB built in to Apple keyboards. No joy, as the device will not fit there and even if it did, it would be under the keyboard body and not usable. Hanging it by the USB tail extension I can use it but it will always move around, still requiring the 2 hand use, unless I scotch tape it. Then, it makes the laptop a little less mobile if I have to remove it every time I travel.
I am also disappointed that despite taking far more repetitions to learn a fingerprint than a 10 year old Microsoft infrared fingerprint reader (sadly not compatible with Mac or even Windows 7 now), it still needs the finger swipe to be so specifically accurate. But, it i doable, and when you get used to it, it does save time.
A plus is that I have it working on an office provided Windows 7 laptop. A disappointment is that it does not store finger prints on the device for MAC users. It does store the fingerprints for the Windows software! So, technically I think I can carry it to different Windows desktops/laptops without having to save fingerprints x 10 x 5 repetitions per finger on each machine, but for each Mac I would have to go through that process.
Based on just how cooperative the seller and the manufacturer have been, and the price, and overall tolerable usability, I am considering getting another unit so I can leave one taped to the desk and one to carry with me or use on the other laptop(s). Or, of course, I will be happy to buy the next great biometric device that comes out for my preferred platforms.
But please be aware of the shortcomings (and advantages) before you order this or similar devices.