Here are the rules. I am looking for the best mounting system for heavy use through Asia on a 6 month self-supported tour through all sorts of terrain. All of the above panniers are very different but I just want to talk about mounting systems here.
Ortlieb is tried and tested and a lot of people like them. However, there are some complaints that if they DO break out in the middle of nowhere then it is difficult to get the highly specialized parts you would need.
Arkel is another top brand but I would like you to consider other bungy-cord based systems as well such as Axoim or Long Peak. I particularly like Axoim because it is very simple. Metal hooks that can be easily replaced with local things and a simple bungy cord available anywhere. Arkels are a lot more complicated but could still be used should the complex locking mechanism fail so I have included them in the "simple" category.
Rixen Kraul I know very little about. They seem to be a bit of a cross between Ortliebs and bungy type systems. Are they reliable for the long haul in the third-world? Does the locking system really work as well as others? Specifically I am considering these Pacific Outdoors Panniers or one of the similar ones from the same company. I really like that their panniers are dry bags like ortlieb but also have a really nice compression system and internally organized pockets. The design looks really well thought out but they are a new pannier maker so I am not sure if they will be reliable?
Here is the companies main page with a lot more information:
Let the arguments commence!