I just upgraded from a smaller safe, and had the same dillema. Went with a dial. No, it is not as fast as electric, but I get faster every time I open it. Down to several seconds now.
If you go with a dial, know that S&G is the way to go. Get one with brass internals, not aluminum. While Browning is one of the nicer safes readily available on a local level, they use an S&G lock (even on the Meddallion line) that has aluminum internals.
For speed, you can work your dial until you have the last two rotation directions to go. Never leave one, as the lock will "tell" on the last rotation.
I still work it from the beginning though, for practice.