I have been using 2 rear Ortlieb panniers (back roller) for many years and recently my brother got me a set of Pacific Outdoor Equipment (rear fender). So my Ortlieb went to my new front racksand the POE on the back. So far I did 2x 4 month journeys with that setup. My brother is a big fan of bicycle touring so I first told myself "what the heck was he thinking" Pacific Outdoor?? Who ever heard of them?
I quickly changed my mind, I have to say I was really impressed with it. They definitely are as waterproof and as tear resistant than the Ortlieb. He got me the Super Rear Fender (t's like 2 panniers yo can attach tgether - and you can add the Boot at the top of it, they all clip together nicely). They have side pockets and some extra storage options in the cover (the bag rolls up but there is an detachabale lid for extra protection and to store stuff that you need to have handy. Both very nice and very practical.
The top hooks are even better and more secure than the Ortlieb (perhaps even stronger) - kind of like on the Arkel but they are not made of metal - just very solid plastic (when the hook is closed the bag is not going anywhere) but I prefer the nice and easy ortlieb system to take the bag on and off (just by pulling the handle). The bottom hook is kind of like the one on the Classic series of Ortileb (just one staright rail where the hook slides on) - and I prefer the oval kind of rail of some of the Ortlieb (the QL2 system) it gives you more option to secure the bag on the rack. But since the top hooks of the POE are so nicely tighten to therack I didn't have any problem with it (I use Racktime racks).
So bottom line, POE came up with some really nice products that can definitely compete with the best panniers, and I believe that when they will be well known Ortlieb and Arkel will have another serious competitor. The only thing, since it was gift I am not sure how much they retail for.