If you can get past the ridiculous price tag, the Ortlieb Vario does exactly what it advertises -- a single pannier that can hook on to a rack or be used as a backpack. The conversion is simple and all the moving parts are reinforced to reduce wear and tear. I commute 2x a week and walk 2x a week, so this has eliminated the need to transfer all of my work stuff from pannier to backpack. The laptop sleeve is and outside pocket are much appreciated details. I'm not surprised they're sold out. Highly recommend.
I used my new 31 liter Rack Pack on one multi day bike tour. I got it because I hoped it would be better than using a bungie net on top of my rack to hold a bear vault of food and crocks shoes. It is far superior to bungeeing stuff on the rack. The procedure to snap it onto the Ortlieb rear panniers works as simply and as easily as shown in the Ortlieb how to video. It rides securely, stays in place well in spite of bumping and jarring over the miles. It keeps stuff together, and protected from the elements, at night in the campsite. After one four day trip it shows no sign of wear. It seems quite rugged, and I believe it should hold up a long time. I'm very happy with it. I talked to one person who had a raccoon chew through an Ortlieb pannier to get food at night in a campsite, and I've heard from others of people they know who had raccoons and squirrels do the same thing. Therefore I keep all my food in a bear vault canister and set it out on the ground by itself overnight, to protect my expensive Ortlieb items.
