Good to know it could be easier in the US to find good oats than in Canada or the UK (actually this is confirmed by me also finding good oats quite quickly in Boston when I was there for a few weeks).
Mostly I wanted to make the point that if you've tried making muesli with oats from a standard shop/super market in a non-Swiss country (likely with the exception of Germany and Austria?), then chances are you didn't enjoy it because they were not suited for the purpose, and it might pay off trying again.
Reading Wikipedia [1] I notice that I should also try steel-cut oats some time (more bran meaning more taste and health benefits?)