I know I am late to the party here, but there are a number of things to consider before you spend your hard earned money. First do your research, look at the construction of various companies and you will find that the basic construction is pretty much the same from company to company. You will pay more for thicker steel, when reading the gauge of steel think of gauge like you do when thinking about a shotgun, the lower the number the thicker the steel. What we call a gun safe is not a true safe, they are Residential Security Containers. The Fire Rating varies from company to company as well, there is no set standard unless it is the UL standard and none of them are UL listed for fire, every company has their own testing standards, they all with the exception of Sturdy use gypsum board aka sheetrock/drywall yep the same stuff as the walls in most homes. Why do they use this, well the reason is simple, gypsum board retains moisture locked within it for years, once exposed to heat that moisture is released and it keeps the inside temp of your RSC cooler than burning point, does this mean your firearms will come through unscathed, well that depends upon a lot of things, far to many to list here. Keep in mind how far you live from the fire department and what is the response time to your home, the farther you live get a longer rated RSC.
I own a Superior Master Series, 10 gauge body with a 3/8 thick solid plate on the door. my advice is this, buy the most protection you can afford and the biggest you can afford, think of it as a lifetime investment because nobody wants to spend their money only to have to buy another one in a few years. They do fill up fast, one thing I did was to install a product called Rifle Rods, I was able to put more rifles in the same area as before, I really recommend them.