Perhaps this is for another thread....
Part of the ongoing Search For the Perfect Camera Bag, I guess. I use a Domke vest myself and it is useful as far as it goes, but I am still searching for the right combination of convenience, weight, capacity, and portability for carrying equipment.
Main problem with the Domke vest is trying to stow my Contax 645 35mm lens (it's a big mother with a front element the size of a manhole cover) and a couple of film backs, and to try to fish them out while holding up the camera on its monopod while detaching the empty film back or changing lenses, etc....I keep all my stuff in a big LowePro "shoulder" (if you are The Rock) bag and carry the essentials in the Domke.
The vest is just another camera bag you wear, and I am still looking for the "right" one.