I toured this summer with a pair of MEC World Traveller 56 L panniers. They were wonderful. I biked through a couple of days of rain and garbage bagged everything just in case. They have a few extra pockets around the bag that are handy for storing quick access pullovers or food. For a three week self-supported tour through everything from +30 and scorching sunshine to 0 C and rain, I was able to fit everything I needed. I will be picking up a small set of front panniers for a longer tour that I am planning later this year for a little extra gear that I will be taking along. The difference in weight distribution using the front panniers in addition to the rear panniers will be nice.

As for the attachment system, I haven't used anything else but I found this system very easy to use and reliable for my tour. I never had it pop-off and it was very easy to remove if I needed to. I was happy with MEC panniers and don't feel the need to spend a lot of money on an upper-tier set. MEC panniers may not be the absolute top quality but I would be willing to bet that a person that buys MEC panniers gets the most value and quality for their dollar spent.