I did buy one a while back from MEC (returned the next day) and when I got it home to try it out it seemed like it was near impossible to get the top closed, which of course means smell gets out. Also, I’m guessing if a bear got hold of it he would take it for a walk with him. You’d still need to hang it high.
Where are you going? Some places won’t let you use these. I personally wouldn’t use the Ursack for bears.
Bears in Yosemite, I think, have learned to open the plastic bear bins too.
For small creatures I use plastic nut containers.
For black bears (which I rarely every see in all my trips into the mountains) I would use bins provided; hang food properly or use a bear bin.
If I were headed into grizzly country I would use a proper, expensive, large size bear bin. An absolute requirement in many spots. You can always put other stuff in it as you eat your food.
As for kayaking destinations, I have never had issues with bears in the places I’ve gone and we have stored in our boats.
I borrowed a BEARIKADE once and it is light, big and strong. But VERY expensive. If I were going to the Yukon, I’d buy one.