I have two backpacks that convert for use as panniers and thought it might be helpful for others to hear about how they compare.
The first is the Two Wheel Gear Pannier Backback, which retails for $149:
https://www.twowheelgear.com/product...ck-convertible
The second is the newly released Po Campo Irving Backpack Pannier, which retails for $129:
https://www.pocampo.com/collections/...=6392136957991
Both work really well as backpacks and hold plenty of gear. Both have nice side pockets suitable for holding water bottles or U locks. Both have reflective accents and plenty of organizational features on the inside. Both include a laptop pocket that holds my large iPad Pro securely. Both latch onto the rack securely. The Two Wheel Gear backback comes with a water resistant cover. The Po Campo is advertised as water resistant. I don’t worry too much about this feature since I use my Ortlieb panniers any time there is a chance of rain. So, in terms of use on the bike and off of it, there are largely comparable.
Here’s the big difference: How they convent between functions and how easy they are to put on the bike. In these two respects, the Po Campo wins hands down.
To convert the Two Wheel Gear bag, you unzip the back of the bag to reveal the pannier clips. Next you unclip the backpack straps from where they attach to the bottom of the bag. Finally, you fold over the top half of the back of the bag and then tuck the backpack straps into a pocket that occupies the bottom of the back of the bag beneath the pannier clips. (The pictures on the website show this more clearly than I can describe it.) The problem with this is that the tucked in straps create a large bulge that can make it challenging to get the pannier clips close enough to the rack rails to attach them. You also have to clip straps at the bottom of the bag together to secure the bag to the bottom of the rack. It works and is secure, but it is clumsy. The video on the web site makes this look like a breeze, but after using the bag for a year, I’ve found in practice it takes longer to do than I like, and I often get my hands jammed in weird ways trying to get the bag on and off the rack.
The Po Campo bag has a much more elegant design. All you have to do is turn the backpack straps over so that they go across the front of the bag instead of the back. Then you attach the bag to the rack using the magnetic strips on the back. There’s also a simple clip on bottom to attach to the bottom of the rack. Simple. The straps even have high-vis neon yellow undersides that show when the bag is in pannier mode. The magnetic strips rest against your back when you are wearing the bag in backpack mode, but they don’t dig in. In fact, I can’t feel them at all. I’ve just used the bag for one day of commuting, so maybe other problems will crop up, but it seems like a fine bag. It was very quick to put on and off the bike and to convert between backpack and pannier mode.
Both are good bags, but for my money the simplicity of attachment and conversion on the Po Campo make it the better choice.