I gave my daughter both a single pistol safe and a 2 or 3 pistol safe (depends on how big they are. Both are combinations with key access in case the battery dies and the combination doesn't work. Frankly I forget how the little one works but I can say the bigger one when opened with out the right combination or the key makes enough noise to wake the dead.
BIOS have pluses and minuses also, most what has allready been said. The other thing is you really should program both hands because if you cut your finger tip badly enough the scanner will not read and not open the safe. Also if your hands are really dirty or greasy same problem, if I remember correctly.
The thing about both those devises is that when you Need to get into them you are going to be less than calm and more then likely fumble the key, miss-enter the combination, or not get your hand in place correctly the first time. All adding to the stress level.
If you had to pick a safe then I would suggest a bio safe, with a barrel lock back up. It's about the only thing I can thing of that will be next to impossible for a child, young adult and for that matter most average adults to pick open. Certainly they will never match the finger prints. And a Barrel lock (like on vending machines) is a world class pain to open without the right pick.
All things to think about, all of them have good and bad points, none of which makes your decision any easier I am sorry to say. Oh ya and to make things less fun you will need to bolt the safe down somewhere/somehow so no one carries it off. That limits the places you can put/hide or mount it. Sorry, I think I have not helped you at all, but it's things some folks forget to consider when they aren't in the business of Security, or LEO's. I can only think to say that you put the weapon up as high as you can and out of sight. Don't take it down when the kids are home so they don't see where you keep it. And then (sorry you didn't say how old your children are) simply take them to a range and let them watch you fire it, and depending on age let them shot a couple rounds while you stand right next to them, watching closely. Maybe even a good idea to rent or buy a .22 for them to shot but only when you or your wife is with them. Not. your brother, aunt uncle or whomever. You really need to be there when your children are learning, even if you aren't the one shooting or teaching them. No offense meant. I was a LEO long enough to have seen or dealt with things I would rather forget, and sometimes I accidentally fall in to lecture mode. I do not presume to tell you how to raise your children or tell you what you may allready know all to well.
