Hello,
I don't know so much about Multaq, but as far as I know, Multaq is also a beta blocker (and a calcium blocker and sodium blocker), when amiodarone is only a potassium blocker, in other words, Multaq have the beta blocker side effects (such as fatigue).
Again, as far as I know, amiodarone is a very strong drug (known as the "last resort" within antiarrhythmics) with possible severe side effects, such as sunlight intolerance, proarrhythmic effects, etc.