I purchased this bag from Wellington Photographic Supplies Paddy was very responsive to emailed questions and really helpful overall. I ended up picking up the bag from the Vivian Street store which is closer to my studio.
I learned about the bag through American photographer Michael Clark in his book Adventure Photography. It has been around for a while and seems popular with photographers who need a big bag that can handle the elements. I had a good few years using the now discontinued Computrekker AW backpack. The AW stands for All Weather and is has proven very helpful shooting outdoors in New Zealand!
Some of the key features that I really like about the bag and why I chose it over other brands and styles:
For those who have a full kit, consisting of 2 pro DSLR camera bodies, and a few pro lenses then this is a comfortable and safe way to transport your gear in potentially hostile outdoor environments. The extra size enables you to pack a couple of strobes and have the ability to light your subject as well, all in one bag. Full disclosure, all the gear mentioned in one bag will be very heavy! This is more a pack in type bag. From there you can take kit out and shoot, its not for street photography with easy access while walking or anything like that.