I've been using the Axiom Typhoon bags for 7 years now and they've been perfect. Bag remained perfectly water proof and the connection hardware never broke.

But now I want to replace. I've tried some Ortlieb Back Roller Classics but, my goodness, are they loud on a bike rack banging around and squeaking. The top of the bag where they attach to the rack is super loud even when using the proper insert. You'd think they'd use some rubber insert rather than molded plastic as, surprise, plastic will rattle on metal. As well, their system for attaching the lower part of the bag to the rack, i.e., that plastic lever-looking thing, never really cinches the bag to the side of the rack and, surprise, more banging as the plastic bounces against the metal.

So, still looking for waterproof rear panniers at about 25L. Arkels are just was too overpriced. Axiom stopped making the model I had and doesn't have a comparable offering that I like. The Banjo Brothers rear panniers look promising, but it's not clear, yet, how they attach at the bottom of the frame.

banjo brothers canvas pannier. the inner liner is a removable water-proof liner. only 60 dollars. used it for a few years now

My wife got me a set of Ortlieb Classic Back-Roller Panniers for our anniversary, and I absolutely love them. You won't regret it.