I am a professional locksmith by trade. The first company I worked for sold, serviced, repaired and moved all types of safes.
Here is my advise and opinion.
Buy something American made. Most American made gun safes are well made. You just need to decide what options you want and how much you want to spend. Definately buy the next size bigger than you think you need. People always find more stuff to put in their gun safe. Personally I would stay away from electronic locks. Yes they are quicker and easier to open. But they are far less reliable than traditional dial locks. I have seen dial type safe locks last 30-40 years without servicing. That being said, a dial lock should be serviced every few years or sooner if it "acts up". With ANY type of safe lock, seek immediate help if your lock has problems. Too many people wait until the safe lock quits working to seek help which costs them a hell of a lot more money.
IMHO, National Security is the "Cadillac" of gun safes. But you will pay a premium for them. Liberty, Fort Knox, Amsec, Cannon, and others are a good choice.
Sometimes gun shows have safe dealers willing to make a good deal. Find out about delivery and installation also. Make sure it's bolted down. I don't care how heavy it is, bolt it down.
And, most people don't realize that items like film, negatives, computer media as well as flash drives and portable hard drives will NOT survive a fire in a gun safe. A special Media Safe is designed for such things.
Please stay away from any safe made in Taiwan, China etc.....
Such as Sentry. I have open, repaired and serviced more of those type of safes that have one problem or another usually due to poor workmanship or design. Often the owners wait too long to get them repaired resulting in the safe locked shut and having to be drilled open. Often the cost of drilling open the safe exceeds the value of the safe. Sometimes the safe are not repairable and parts are non-existant. Most of these safe owners get highly irrate when they can't access thier guns. This statement is not intended to offend anyone. But it's simply my experience with Sentry.
I would certainly shop around locally before plunking down a wad of cash. Some locksmith shops have good deals and may be able to deliver and install. Often the big box outdoor stores are way over priced.
Good luck.