The short answer is there is no difference. An immigration consultant is just as qualified to provide you with immigration services.
Consultants also have the ability to represent clients for any immigration related appeal. Most people think that they have to hire a lawyer when it comes to hearings and appeals but that is incorrect and a licensed immigration consultant is just as qualified to represent you in such cases.
We actually recommend hiring an immigration consultant instead of an immigration lawyer. The main reason for this is the difference in the fees that are charged. You have to ensure that your representative is authorized, licensed and competent. You may do this by confirming with the Immigration Consultants of Canada Regulatory Council (ICCRC)