The most important difference is in the attitude of the two countries towards new immigrants. Generally speaking the United States State Department takes the view that there are enough people in the U.S.A. The feeling is that America does not need any more people. That is why, by and large, the American government does not publish brochures on how to immigrate to the United States and what steps are required. Immigration in the United States is seen as a tool to help the economy. Apart from family reunification and political asylum cases, immigrants are seen as needed only insofar as they can help American employers expand their business. Economic immigration is geared to the workplace and any skill shortages that exist.
While Canada also has geared its economic immigration to the Canadian market, Canadian government attitudes are not quite as restrictive when it comes to new immigrants as US attitudes can be. Canada is a wide open country that still has a need of new immigrants - at least more so than the United States. By and large there is not the congestion, the density of population, the gridlock associated with large populations in big cities that is found in the United States. These factors all influence the immigration process.
Another difference is America's reliance on work-related visas verses the Canadian point system. In the United States immigration is based on the job offer. The job offer is at the front of immigrant visa processing. This is not entirely the case in Canada. Canadian immigration operates on a point system. Would-be immigrants are assessed on the basis of points for various positive attributes such as age, language skills, occupation and work experience. Immigrants who have a desirable occupation can actually immigrate to Canada without a job to go to. Examples might include the therapy professions, and certain welders and mechanics. The same is true for Canadian business immigration. In the United States business immigration is still closely associated with job offers - except for investors. In Canada, however, entrepreneurs and self employed business persons can immigrate without job offers.
Two other important contrasts are worth noting. American immigration often involves an adjustment of status from a temporary work visa to permanent resident status in the country. There is no equivalent process in Canada. Canada discourages attempts to immigrate from within the country. America tolerates it. The two-step process is more related to American immigration than Canadian: first one obtains a temporary work visa then adjusts to permanent status. While this can happen in Canada it is more the exception than the rule.
The last important difference is in the area of caregivers. The American caregiver program is riddled with difficulties involving labor certifications. The Canadian caregiver program is a model of a good immigration program for all countries to follow. It is the only program we are aware of that actually enables those without money or status to earn their way into Canada by working two years for a family that needs a caregiver.