Just bought an excellent Nikon F3 that looks mint other than the illumination for the prism is gone, which is common. And the excellent lens is also what I would call mint minus, no defects, just older. The BGN lens I bought looks and feels like something I would use everyday, no issues at all.
In the past I bought a BGN 180mm APO-Symmar that was also at least excellent. The one time I needed to return something it was easy and seamless. Of course if I lived in Australia it would be a hassle and if they rated it excellent then they are at fault here and should help with the shipping.
My take on BGN is that it can be a gamble, some things are truly beat-up bargains, others are simply good users with a few minor signs of use. Excellent should be professional grade and operate perfectly.
Knowing they have a good return policy and a large inventory is so much nicer than buying from some unknown online, it is worth a premium. And oftentimes they are selling for less than the questionable sellers so it's silly to risk dealing with eBay or forums when you have the option.