Ortlieb panniers are a no brainer for most cycle tourists. They are waterproof very durable and lightweight. They also come in a good range of colours. There are alternatives though. Vaude also make excellent panniers, they are a bit more rigid, larger capacity with a different mounting mechanism. Pip has had her Ortlieb Waterproof Classic panniers for about 3 yrs. There was a good deal on the Vaude Aqua panniers at the same time so I plumped for them. Mainly because they can carry a little more. So how do they stack up in day to day useage.
Quality, there is little to choose between them. They both are fully waterproof and are showing minimal signs of wear.
Weight, all 4 Ortliebs check in at 3.15kgs with a total capacity of 65 litres working out at 4.85g per litre
the Vaudes weigh 3.85kg with a total capacity of 76 litres working out at 5g a litre.
The Vaudes however are more rigid with a plastic panel at the back that resists flexing. The Ortliebs are more flexible and Pip has to strap them to her front rack to stop them unpopping from retaining arms when she goes over a bump. The fixing clamps are also different, the Ortliebs have a retaining clip that locks into place when you release the carrying handle. The Vaudes have to be pushed laterally and they clamp themselves solidly to your rack. If you fit the right spacers this makes for a solid fix and your panniers will not rattle around.
The Ortliebs come with a integral strap that you can use to carry them over your shoulder, the Vaudes come with have a separate strap that you have to clip on. However you can buy a lightweight padded back support that turns one of the Ortliebs into a back pack. Really useful when you are touring and want to trek off into the hills.
I would recommend checking out the Vaude Aqua panniers as they have some advantages over the Ortliebs. We are both very happy with our panniers, they are a cornerstone to a successful tour.