For another thing, the Ally has a foam bottom that sits between the frame and the skin. That does a lot to help cushion the canoe against blows from obstacles in the river, while adding some extra flotation. With a little more flex in the base, as well as in the frame, the vessel can dissipate the impact from hitting rocks or logs, say, while flexing a little as it slides over obstacles. It also bounces around less on whitewater.
The Norwegian-made Ally's most popular model is the 815 ($1,795; www.bergans.no), which is big enough for two people and a fair amount of gear. It's 17 feet long, not quite a yard wide, and at 45 pounds very haulable.
For everyday use around a cabin or a location where transportation is not an issue, any aluminum or fiberglass canoe will work just fine. But I think the fact that the Ally is foldable, plus its sturdy design, are both big positives when your canoeing takes you far afield.