We have used Carradice for about 5 years.
This week, we took delivery of a pair of Ortlieb back-roller plus.
They are vastly superior to the Carradice in every way.
1. The Ortlieb method of adjusting the hooks to fit the rack requires no tools. It's simplicity itself. With the Carradice, you have to use a cross-headed screwdriver and the screw then holds itself in place by attempting to bore a hole in a metal plate. After a while, this not-very-good-quality screw starts to round off at the head end.
2. The Ortlieb are lighter.
3. The Ortlieb are waterproof. Carradice keep the water out for a while, but not for ever. Of course, bags designed for clothes recycling can eliminate water. NB We haven't yet used the Ortlieb in a prolonged downpour, but others have spoken of their uncompromising waterproofness. I have a recollection that, on our arrival at our B & B in Fort Augustus on our LEJOG 4 years ago, everything we possessed, having spent all day in the Carradice panniers in the pouring rain, was wet through. I don't think we had been especially careful with plastic bags.
4. The Ortlieb are as voluminous as the Carradice rear, but much bigger than the Carradice front. However we tried the Carradice rear on the front of the tandem last week. It worked - just - but the ground clearance was so low that I had to corner more slowly than I otherwise would, else we grounded the panniers. The Ortlieb have much better ground clearance, and extra luggage just makes them taller. I don't anticipate any problem with the centre of gravity being too high.
5. The Ortlieb delivery box bore a large message "Made in Germany" on it. Admittedly, there were no personalised messages from Hildebrand, Heidi or Gretel on them, but that doesn't mean that they weren't made with loving care.
6. Once, the night before a tour, I had to sew up our Carradice pannier because a seam had come undone.
7. The one great advantage that the Carradice panniers have over the Ortlieb is that quirky Britishness - being not quite top quality but wearing that as a badge of pride.
We also have a very large set of Altura panniers. Although massive and having given us no problem so far (although their very massiveness may have been a contributory factor in Mrs. Wow's Danish tumble) their method of affixing to racks is just not very good, and they won't fit at all on the tandem's industrial-strength Thorn-designed front rack.
Andrij, of this parish, tells that the Ortlieb Plus, which are about £30 more than the Ortlieb Classic, contain no PVC and therefore are environmentally more acceptable. The Classic also have an inferior fixing system which requires allen keys.
The cheapest place we could find for the Ortlieb Back-roller Plus was Spa Cycles, at £106 per pair delivered. I ordered on Monday evening and they arrived Wednesday morning.