This is a difficult question which largely depends on your needs and wants, but here are the differences:
A fixed rate mortgage is when the mortgage rate and mortgage payment remains the same for the whole term of the mortgage. An advantage is the consistency, so if you do not like surprises, this may be the style for you. Disadvantages are the much higher penalties for breaking a mortgage, which limits your flexibility when moving to a different house or upgrading to better mortgage.
Variable rate mortgage is when the mortgage rate moves with fluctuations in the bank’s prime rate. As a result, mortgage payments may vary during the term of the mortgage. A minimum term commitment is often required, usually 3 years. You may have the option to “lock in” the mortgage at a fixed rate during the term with no penalty or additional expenses. Advantages are a much lower rate compared to the fixed rate on offer at the same time the penalty is much lower with maximum flexibility to manage your mortgage and save you money. Disadvantage is that this rate fluctuates.