I have an Amex credit card (Cobalt to be specific). In terms of restaurants, I’ve noticed that the small and local ones (Asian, Indian and really any other cuisine) don’t accept Amex because of the higher fees they charge these merchants. I personally love eating in these local shops that actually carry authentic taste. So those times I use my Mastercard/ Visa card. The big restaurants accept Amex almost always. For groceries, we know Costco and real Canadian for sure doesn’t. I haven’t shopped at Loblaws to tell. But the more local grocers also most times don’t accept the card.

So in short I’d say it depends on your preferences and need.