When it comes to choosing a backpack for packrafting, there are essentially 2 ends of the spectrums to consider- a fully submersable dry bag with shoulder straps with the other end of the spectrum being a lightweight backpack made of water resistant material.  There is no "perfect" packrafting backpack for everyone as it greatly depends on likelyhood of full submersion of the backpack, weight carried, miles backpacked and a number of other factors.  The Animas lands somewhere more towards the dry bag with shoulder straps but is a lot more backpackable- it has a waist strap as well.  It is a full dry bag, meaning if it is properly sealed everything should stay dry in the case of submersion.   It's smaller size makes it ideal for day trips, single overnights or weekend trips for ultralite packers.  
 
The Animas is Watershed's most popular backpack style. 
Removable, padded shoulder straps
Durable top lug handle
Removable waist belt
Currently Available in Smoke Green Only.