I sweat tons, and found myself unprofessionally drenched when I biked to work with a backpack---even if I biked pretty slowly on a pretty cool day. I've since switched to the Breezer BizPannier and find myself a much happier commuter. I particularly like that it comes with a shoulder strap and that the rack attachment hardware zips off. It is an attractive enough bag that I use it as a shoulder bag on days when I take the train to work or when I travel for business. Also has laptop sleeve and rain cover. One warning only: at 17 inches wide there wasn't sufficient heel clearance due to the relatively short chainstay on my road bike. Purchased the Jannd Expedition rack, which is three inches longer than your typical rack, and that pretty much solved the problem. I'd take a look at the Arkel Bug if you think heel clearance may be an issue. The Breezer bag is actually made by Intertia Designs, and you can buy it for a few bucks cheaper through them, but I find the version you can get through Breezer far more attractive. Hope that helps.