My main bag currently, bit of a tight fit with the Tamron 150-600 mounted on the 7D but I can still also get in the 6D and 180L.
Very useful features of these bags are:
a) Place on the ground and go through the back for the main compartment so your cloths remain clean and dry.
b) Two straps on top for securing additional clothing layers.
c) Large pouch on the opposite side from the main compartment for odds and ends and small items like hats, gloves, reflectors, batteries.