I had been contemplating the purchase of the SpiderHolster SpiderPro Dual Camera System for a few months and decided to take the plunge. As a wedding photographer in Maine, my busy season is about to get under way, so I figured it was a good time. The two reasons I decided to invest in this product are: chronic shoulder and neck fatigue from DSLR straps and because I work without an assistant. Lugging around lighting equipment is not a fun task when you have multiple cameras swinging from your neck, especially without any help.
The SpiderHolster is not cheap. For the dual system it is $230 USD. For this price I expected quality and so far I have not been disappointed. The belt is solidly constructed from a rugged nylon and the clasp has a safety release button so you don't inadvertently dump your gear. The holsters themselves are solid pieces of machined metal attached to pads that rest on your hips. The pads work really well and even with a heavy DSLR (in my case the Nikon D700 with battery grip) are extremely comfortable. To use the holster you mount a small plate and pin via the tripod mount on your camera. The pin you attach to the bottom of your camera then slides into the metal holster.
My biggest fear about the SpiderHolster was that my cameras would bounce around and not feel secure. Considering that prosumer DSLRs go for thousands of dollars, this would not be ideal. My fears were quickly put to rest as even while walking briskly my cameras barely moved. The belt also allows for a wide range of motion and I didn't find it restrictive at all.
My only gripe with the system is that the second holster does not come attached and you have to put it on the belt yourself. This takes about fifteen minutes. You pay an additional $100 for the dual system, so I thought it would have been nice if they attached it for you.