I have Vaude Cycle 30 pannier/backpack. Takes seconds to convert back and forth which is handy since I often take my bike on the train. There are long flights of stairs at one train station, and it's nice to be able to have the pannier comfortably on your back while you are porting your bike up and down stairs or looking for train rack-space. Came with a rain cover, but I wish it has a mesh outer pocket for gloves, a snack, periodical, etc.