Quoted: I'm buying a 25 gun safe tomorrow (probably an AmSec or Liberty but we will see) and it will be with a mechanical dial lock, not the electronic keypad.   Think about it, a decent safe can last you 40 years or more assuming you don't outgrow it or get too old to play with guns any more.   How many pieces of electronic gear do you own right now that are over 20 years old?   10 years old?    I'm an electrical engineer by training and I guarantee  you that electronic locks are more likely develop problems over the decades.   All it takes is for one key pad, electrical contact, solenoid, or integrated circuit to glitch and you are screwed.   Mechanical dials aren't perfect but sometimes old school is better.

Regardless of whether it's electronic or a manual dial, for a safe to last 10, 20, or even 30 years you need to have it serviced by a certified locksmith annually or bi-annually, infact this is actually required by some of the companies like Liberty which offer lifetime warranties, the warranties are only good if you have your safe serviced every year.  

As long as you have it serviced every year like you're supposed to, then there's nothing to worry about as far as the electronics go (unless you have a POS like a Sentry).