Marcus T.wrote a review of Patagonia Black Hole 60L Duffel Bag - 3661cu in on August 29, 2015
Familiarity: I've used it several times
I have the XL. 120 L capacity, I believe. I have used it in pretty rough conditions -- cold, hot, dry, wet. An important feature of its water resistance is that it's also quite dust-resistant. This protects equipment, electronics, supplies in the desert.
I'm fairly confident in its durability -- I haven't discovered any weak points. So even if you're traveling and its contents get bashed into a jingly mush, you're unlikely to lose bits through holes in the fabric or opened zippers.
Its size, geometry, and D-shaped opening gives a lot of flexibility. I recently brought a hand-juicer back from a trip overseas, and couldn't get it to collapse to fewer than about 2.5 ft in length, with a really awkward shape. I bought the first for hauling equipment but like it so much I just bought a 60 L for regular travel.
One useful addition to a future model would be a lightly colored interior, so that things stand out in low light.