As they would say: When you start with a company, you tend to stay with them especially if the competition doesn't offer what you are looking for. THe 5588 is a big bagand when it's packed it is heavy. The shoulder straps and waist belt are well padded, very durably constructed and very comfortable especially if adjusted accordingly. It very customizable and can carry alot of gear. When I say customizable, I am referring to taking all the padding out and redesigning the interior according to your needs.
DigitalMan on Amazon said, This bag "can carry alot of gear (meaning I could get all the gear I own in it, including my Macbook pro). I have both a D80 and D700 body, the 14-24, 24-70, 70-200 and 105 f/2.8 lenses as well as the 300 f/4 (all bulky and heavy). Then I have a 50mm, 2 teleconverters, two SB flashes, several filters, batteries, charger and miscellaneous accessories. I also found the tripod holder more functional, secure and to have better weight distribution and balance than some of the other bags I tried. Fully loaded with tripod on board I am at 36 pounds with this bag." This is close to how I travel.
The double coated, weatherproof 900 denier PolyTek backpack with thick, closed-cell foam is another reason to invest in a backpack like this. If you do not have that much gear, you can purchase the Tamrac 5587, Tamrac 5586 and Tamrac 5585. I have the Tamrac 3380 Aero. It was my first pack for over 6 years and I still use it (back up back). The shoulders are not as padded like the Expedition Series but it is strong, waterproof and durable.