I think if you go to Bankrate you should be able to calculate a loan and decide if a balloon payment loan is best for you.
The good thing about a balloon payment loan is that you can refinance a balloon loan and not have to pay the full balloon amount at once.
This will extend your loan payments and probably offer you a higher interest rate, but you always have that option with a balloon loan payment.
I think if I were a real estate investor, I would go with a five year adjustable rate mortgage. Here the first five years of the loan are at a fixed rate and then the subsequent years adjust to a variable rate.
While the payments will be much higher after the payments reset, you may not necessarily need to refinance like you would with a balloon mortgage because you only have to have a few hundred dollars a month to pay not payoff the entire loan.
Also, refinancing a balloon mortgage will cost you money so if you plan on paying off the property quickly or plan on selling within the next few years an ARM loan might be better than a balloon mortgage loan.