I used one of these bags on my across USA ride last year and it worked ok for those days when I used it (bad weather...to carry rain gear, etc). On the plus side: it is light, carries a rain jacket, warm gloves and additional snacks, is easy to take on & off, the seatpost clamp is unobtrusive, the bungee cord on top is convienient to quickly stash a jacket, etc. On the negative side: it has a low top weight limit of around 5 pounds and you cannot use a carbon seat post (I changed mine to an aluminum one because of the warnings about safety). Also, if you have a small frame you cannot use the regular size...so I purchased the small one for my 52 cm frame. For my occasional use on this trip, the bag met my needs.