I got this pack a couple of months ago and after using it on multiple trips, I finally confident enough to give it a solid review. I do have to say that I was already using the Peak Design Pro Clip (Game - changer!!) so I had high expectations for their backpack. I was originally using the Crumpler Karachi Outpost Backpack - which I will keep using for my mini photo sessions where I take my large Nikon D800. The large cameras don't fit that well in the peak design 20L unfortunately. But it does fit my Sony A7rii with the zeiss 24-70mm, nikon 85mm (+ adapter), and a nikon 14-24mm if needed.
This past weekend, we went on a 1-night backpacking trip into the Cascades and I had to choose between taking my peak design & my Osprey backpacking bag. The choice was clear - Peak Design all the way! Honestly, I sometimes hate the bottomless-pit feel of my osprey and it was great to be able to sub-divide all my things and know that my camera was safely packed. I just had to tie up the sleeping bag + heavier clothes into a compression sack that went on the front of pack and stuffed my 2L Osprey reservoir into the laptop compartment - PERFECT. Obviously, for a longer trip, this pack wouldn't perform so well (ie no padded waist strap, etc). But I think I will continue using the Peak Design for short backpacking trips.
Material: Waterproof - I love it! I've definitely dragged this pack through the ringer - muddy trails, climbing, backpacking, stormy downpours. My stuff has always stayed dry and pretty clean for what I've put it through. I do have to make sure the top flaps are tucked in so that water doesn't get into it.
Usability: It's definitely a bit confusing when you first get the bag - there are so many features packed into this thing! But it's great because there is a lot of versaility and I imagine that people would be able to use this in many different ways. As of now, I only use one side of the pack. The other side, I keep locked. They've really thought things through on placement. I was really impressed that I could have a huge compression sack hooked to the front and a water bottle stuffed to the side, and still be able to easily access the side zippers and grab my things.
Warranty: This past trip to Seattle, I had flung my backpack into my Uber and low-and-behold..the latch snapped clean off. Eek!! I reached out to Peak Design right away and they had a new backpack sent to me within a week. Talk about lifetime warranty! I remember I had some issues with my capture clip as well for a bit, and they sent me new parts 2-3 times for it.
Cons: The only thing I've seen so far is that sometimes the straps slide out of the magnetic closure system on the sides after much use. Not too annoying; but something to note. Also, there has been a couple of times where I've closed the side zippers on a full pack, and the zipper actually split in the middle! Scary for my equipment. I've just learned not to stuff too much into it. Also, when I don't have my pack fully packed, my camera equipment rolls around a bit in there. Even within the tightly confined dividers. This really only happens when I have my smaller Sony A7rii in there. With my D800, it's such a big camera that it fits snug.
Price: For around $260, this is definitely an expensive bag but I think it is well worth it due to its versatility and functionality. I love that I can expand on the bag and it gives me opportunities to latch different things onto it - very important for a photographer since we're always lugging around heavy things. When I was first on the market for a new backpack, I hated the idea of spending a ton of money on a backpack that only had one use. But this backpack is truly an 'everyday' backpack that takes all that I throw at it.