I purchased this bag to replace my LowePro Flipside 400 (an already massive bag, which has proven itself time and time again to me). I was not prepared for just how more comfortable the HB-205 was over the Flipside 400. The harness system is a godsend, especially when carrying heavy lenses. I use it frequently with a Canon 1D mk.IV, a Canon 70-200 f/2.8L IS II USM, a Canon 400D (backup body), Canon 17-40mm f/4L USM, Canon 1.4x Extender II, Canon 430EX II, and a fair number of accessories. Carrying the whole kit is surprisingly easy. I suspect that it will fit my Canon 400mm f/2.8L IS USM, however I've had no reason to try it yet as it usually ends up being carried by hand.
The interior of the bag is extremely soft and durable, and the dividers can all be split up and rearranged to suit your specific needs. This bag has no laptop compartment, however this is not a problem for me as I can see no reason that I would ever want to take a laptop out with me.
The side pockets are perfect for holding water bottles, and the rear webbing is perfect for attaching carabinas to so you can attach other equipment to it if you are not using that area to carry a tripod or monopod.
Accessories included with this bag are: webbing straps, tripod foot holder, all-weather cover and a camera neck strap with bag attachments.
My only small complaint is that, unlike the Flipside 400, you have to remove the bag to access the camera compartment, however its a small price to pay for the comfort level and amount of storage provided.
I would certainly recommend this bag to anyone who wants to carry a decent amount of equipment into the field. The build quality surprised even me, which in my eyes was even better than that of Lowepro, with whom I have a great affinity. The bag is due to go to Yellowstone, WY next week for three weeks of outdoor photography, and then skiing with me to Avoriaz, France in mid March. I'm confident in its ability to stand up to everything I plan to throw at it.