biometrics suck! Sorry to say it that way and anybody that buy those biometric systems just give the gun grabbers more ideas and reasons to bring in more of that stuff.
There are severl videos on the internet, that explain how to copy fingerprints with normal everyday household goods, such as a inkjet printer, some super glue, a digital camera and a fingerprint, that can be found evrywhere in your house.
The same method was successfully used to fake prints on biometric payment systems.
Companys, like Armatix live from those systems, and from trying to sell smart gun technology, biometric blockings systems for firearms, etc. and are lobbying with several goverments.
Also having an emergency opening key only reduces the safety factor, since you have to hide it somewhere and the quality of those emergency locks are mostly of very poor quality.
In my opinion, nothing will go over a mechnical or elektronic PIN locking system.
Sorry to state this so directly, but I just do not understand any gun owner, that will buy a biometric safe out of his own free will.