In the last year, Ive bought one Browning BAR used, and 3 new Browning pistols, all went very smoothly.
Massive Caveat, its not the website, its the seller, no different than ebay. If you dont know what you doing, buying, or what its worth, you will probably have a bad experience.
If youre on your game, it should be fine. My BAR had a 3 day "no reason" return. I received the gun from my FFL, drove it too a Browning dealer/gunsmith and had it inspected and appraised, the guys reply " Id buy it ", turned out to be next to new. I got it at about half price with a Leupold scope on it, in like new condition.
The 3 pistols I bought, I only used gunbroker because all of my local gun dealers could not get their hands on one, as well as the gun shows I went to I could not find them.
The site is fine, you just have to know what your buying, look at the sellers feedback, and if you worried about it, make sure they have a return policy.
I now buy about half or more of everything I need, less my groceries, on line. Its just too easy. I also live on a Farm and not in town, so that makes a big difference too.