Quick question: Is 3.65% a good rate for a 5/1 ARM loan which is interest only? Loan amount is about $600K

I don't know where these people are pricing loans at, but that rate is high. Check out Met Life Home Loans in your state for comparison.

It is a good rate, what is the APR along with this rate? Also are you planning on selling or refinancing this property in less than 5 years? If you are planning on keeping the home, and interest only loan on an Ajustable is not the best loan to take. If you are just looking for a short term savngs and plan to sell the property, then it could be a wise decision. You also want to look at how much you would save by doing the ARM and the closing costs involved. What is the breakeven point? The amount of months it will take you to recover your closing costs, by the amount you save each month - assuming this is a refi...

you can never discuss rate without fees and fee without rate to know if a deal is a good one. You will know if this is a good deal if the APR is close to the rate. If the APR is more then .125% higher then the rate you are probably paying a point.

depends on the fees involved and the loan to value ratio. what county is the property in? Is this an agency jumbo arm?