I have the Trek Interchange rack and panniers as well as the bag that sits on top of the rack. I love the versatility of having all three pieces to swap out as I need. I use the two panniers for commuting with my laptop in one side and my change of clothes in the other. They snap in and out very quickly and are very secure when clicked in. The panniers have yellow rain covers which I've never used since I'm a rain riding wimp. They can be pricey but I found a set a 'last years' model at a lbs and got a pretty good deal.