Honestly, this is a horrible time to take out an ARM. With the recent government looting of the Cyprus citizens' bank accounts the markets are in a state of flux and there are real fears the FED is going to do the same thing here eventually. If they did do that and you're on an ARM you would absolutely get effed in a major way. ARM's are very risky when the markets are sketchy and they've rarely ever been more sketchy than now.
http://www.foxnews.com/world/2013/0...gives-cyprus-4-days-to-find-bailout-solution/
Basically, the banks were supposed to steal or *tax* every bank account like 10% and give the money to the FED/Central Bank/IMF/etc in order to avoid bankruptcy. They recently decided not to do it, but you see here they're getting massive pressure to do it anyways. The speculation is that Italy might be next after they finish with Cyprus.