Traditionally borrowers paid a premium for fixed rates because that was the price for buying security that your repayments for that period would not change. 

However is the current climate fixed rates are now cheaper than the variable rate loans in a lot of cases.  At the start of the year we saw some great fixed rates, these are slowly increasing but are still good value.  Most people argue that in the variable vs fixed debate no one is the clear leader in the long term.  So you should make a choice based on your personal stand on risk. 

If you are the kind of person who has a low risk stance then fixing you rate will give you peace of mind.  However if you are wanting the flexibility and features in your loan then a fixed option may not suit you. 

When you fix your rate penalties apply for breaking this fixed period i.e if you want to refinance or sell during this period.  Investors who rely on rental income might find a benefit in fixing as they can be certain of their return. At the end of the day the best option if for you the borrower to match your loan with your outlook on risk.