While browsing internet retailers, I came across two more options,

* Black Diamond Cirque 45L

* Sierra Designs Flex Capacitor 40-60L

Black Diamond is known for its backcountry gear, and 45L Cirque makes its way into tops of online reviews, along with Osprey Kamber. The information on the Capacitor is more scarce. The previous season version of the latter is available at throwaway price, and the capability of resizing the pack from 40 to 60 liters is appealing. On the other hand, my primary goal is to find a specifically winter backcountry oriented backpack. Can anybody compare these models against each other?