Fixed mortgage of 5/1 7/1 arm

[Julia France]

I'm about to purchase my first investment property/vacation home. I have been offered a 5/1 arm at 4.875%, 7/1 arm at 5%, or fixed rate at 6.75%. Would it be a bad idea to go for the 5/1 arm at 4.875%? Does refinancing at the end of the 5 year arm cost the same as it would to refinance a fixed rate? I have done my research but also want the opinions of the pros.

Any advice would be great. I have had my offer accepted, now getting a loan provider.