Whatever you do, don't buy anything from Liberty... Now that it's common knowledge they'll give up your manufacturer's master code without a warrant, those safes are at risk.
I'm pretty sure I have that one. The rule of thumb I use is to divide the number of guns it says it can hold by half, and use that as a realistic number.
Apart from getting mold in the safe (minor basement flood) it has been great.
Golden rods do a nice job, if your space isn't too humid to begin with. I also keep a dehumidifier in the room, so the outside air is maintained >45% RH.
Of course, flooding is going to be another problem entirely.