I use this thing every day on commutes, while mountain biking, or keeping some extra clothes on a winter ride. Once I even filled it with 10lbs of fruit from the grocery store, and though it never faltered, it did get to swaying noticeable upon acceleration. This I hear is a common side effect of saddle bags without support stays, which is something I personally wish I had done more investigation on. It can also be a bit finicky to take off and on if you switch bikes around much. Nevertheless, this pack is well constructed and will keep your stuff dry in all but the worst of conditions. Maybe not the most innovative on the market, but it serves my needs quite well.