Is anyone here-

[Ghoulish Delight]

Generally, interest-only is not worth it. And at $150/month difference, I'd say definitely not. You will be gaining zero equity, and at the end of the 10 years you will have the same principle to pay, except now you only have 20 years to pay it instead of 30, so you can guess what that does to your payments.

You're probably better off at this point making do until you pass the 24 month penalty period. You'll have saved up some equity and will likely be able to get a better deal.