Be aware that the success rate for bighorn in Canada generally runs from 50% to 75% with a top quality outfitter.It is by no means a sure thing.As for the ease of hunting bighorn,it depends on the area,and the hunting method.I have hunted bighorn both by horseback,and by backpack and while horseback hunts are generally easier,backpack hunts can be very tough.Temperatures can range from 90 degrees in the heat of the day,to well below freezing in the early season.In the late season temperatures can easily reach -20 degrees, with two or more feet of snow.
I have not hunted dall sheep,so I can't offer a comparison.