Build quality of the pack is the best i've seen. I haven't tested how water resistant it is, but I am confident it will hold up very well espcially since water would have to make it through the outer pack and the camera shell to do damage.
All the compartments in the camera shell are movable. They are velcro attached (very securely) to the inside and can be removed/moved. The entire camera shell velcro's in and out. It fits all my gear:
D70 w/ nikon 70-300G zoom
nikon 18-70 ED Dx
nikkor 50mm 1.4 AIS with 2 macro extension rings
nikkor 55mm 2.8 macro
nikkor 55mm 3.5 macro
nikkor 24mm 2.8 AIS
Canon s50
Chargers, Power cables, usb cables, filters, ipod, heaphones and laptop.