We actually sell on Guns.com
To put it simply Guns.com is the amazon set-up of the firearm industry. Basically each dealer can submit the price they want to sell each gun at and when one sells they go down the dealer list for that firearm (usually by price).
So overall it should be safe. The main problem people will run into is they purchase a gun and then a bunch of dealers may no longer have inventory or some mark it as available and take a long time to ship. Guns.com is starting to crack down on this and seems to be improving a lot on that.