As mentioned, there has been a lot of discussion on some of the gun boards; read a bit on gunbroker.com in the general discussion forum
All of my comments are based on several years of safe service and repair. The thread quickly turned to gun safes; they usually do. All gun safes are basically the same--a thin outer shell of sheet metal and one or two layers of sheetrock for insulation. Sorry, that is it. Liberty has been mentioned and it is one of the better gun safes. You dont want HF version, or the entry level I have seen at Atwoods etc. Suggestions to look for when shopping---read the specs or ask:
Dial lock. S/G is good and frequently used. Electronic keypad locks will give trouble; not a matter of "if" but "when". Look for a 4 number combination rather than a 3. Someone mentioned a 5; the last is a drop number where the dial stops turning.
Method of changing the combination? Key change is frequently used. Do not use any predictable number in your combination--NO birthdays, phone number, address, etc
Relocker system. If someone tries to bypass the lock, they will trip the relocker and make it much more difficult to get into the safe--even by a safe tech
Hardplate or drill proof located behind the dial and handle area
Active bolts on top, bottom, and open side of door. A passive bolt on the hinge side is fine.
There are often good deals on older safes. Most are a bit smaller than the standard gun safe, but they are usually of heavier construction, and more secure. Check C/L, the local papers, any "thrifty bargain" papers, and any business that is going out of business.
Not uncommon to find one where seller does not know combination and the door is open. Buy it cheap and have lock read and reset--takes about 30 min. If door is closed and no combination, keep walking
My safe is a double door Mosler approx 5 1/2 ft tall, has 4 number plus drop combination, and weighs close to 2000 pounds. Doors are 8" thick, sides are closer to 6", inner doors are 1/2" plate steel. Cost was $50 from a furniture store going out of business.
Good luck. Got any question, just ask