If you had a crystal ball and could look into the future and forecast on whether interest rates would rise or fall this would make for an easy answer! With mortgage rates on a continuous downer these days having a variable rate right now would be brilliant! However rates can easily swing the ... other way and go back up from where they came.
So, variable or fixed? With a variable rate, your monthly mortgage repayments can rise and fall with general market interest rates. If interest rates rise in the future you would be better off fixing but then again if interest rates fall (like we have seen in the past few months) you would be better off with a variable rate. No one can predict how interest rates will go, whether they will rise or fall. The benefits of a variable mortgage usually include a better rate and more flexibility towards your repayments.
Fixed rates can be more expensive than variable rates and are usually inflexible. However a big attraction of fixed rate mortgages is the interest rate is unchangeable or "fixed" for the length of your loan. This is of great benefit if you have borrowed your absolute maximum and cannot run with the risk of interest rates rising in the future.