An interest only mortgage is good because all you pay back each month is the interest. This means that you are not committed to paying a certain amount of money back each month. However, unless you have good self discipline this may not be a good mortgage for you because you will have to commit to investing some money each month in order to pay it off. It could be tempting to spend this money on other things and just hope that somehow there will be enough to pay off the mortgage when it is time to do so, but no one can wave a magic wand.