There are some real important items in a good safe. Like material thickness on safe body and door. Also how many locking pins and there Dia. And if the hinge pins are hidden. Then there is the fire rating on the complete safe.
I looked at a lot of safes and ended up with the Fort Knox 7241 Defender.
http://www.ftknox.com/redesign/safes/defender.htm
The Electronic Keypad lock is really the way to go it's been around a long time now and mine works great. Mechanical locks also can also fail so anything can happen. But if they were a problem Fort Knox would not sell the The Electronic Keypad lock and they sell a lot of them.
Any real questins about their safes call them ask for Dave he has all the answers and is there to help when help is needed.