+1 for the Ortlieb. They are basically the standard for long distance tourers. Not light or cheap but tough enough to survive crashes and remain waterproof. I think it's the same material that's used for cavers' bags.
Better weight than wisdom, a traveller cannot carry
Have had 3 crashes this tour, Ortlieb panniers are fine. Like the locking top clips . One tip make shure the panniers don't move back and forward on Aluminium racks. Tubus racks are fine the metal is rubbed to a shine. Tip buy and fit extra lower clips if not using the gravel bags.Have rubbed the paint away, almost started to eat into the aluminium. A post somewhere said his rack failed due to the clips rubbing through the aluminium tubing on a rocky trip.
Ortlieb city rollers for the daily commute.
Take whatever the weather can throw at them and just lift off with no fuss.
Two and a half years in and ( with a quick wipe down) they're almost like new.
To quote Mr Rolls (or was it Mr Royce?) - "The quality will be remembered, long after the price is forgotten"