Either is good. Costco is cheaper, but not all Costco stores offer it. Not all SDM stores either, but many more. Appointments are needed at both in most cases.   There will be changes made to the ArriveCAN app. Whether this will mean eliminating the list of all countries visited remains to be seen. As no testing is required, irrespective of your itinerary, I can't see them requiring the additional information, but time will tell.