There are a few problems with Plantinga's MOA. The argument is logically valid but not necessarily sound. The conclusions follow from the premises but the initial premise can't be demonstrated. It's troublesome to demonstrate that a "maximally great being" is possible, or even conceivable. That's further confounded if you view "greatness" as a value judgment. At the end of the day, that leaves us at "If god exists then god exists."
I also take exception to Plantinga's use of the term "God". Christianity is the only religion that refers to their deity in this way, so it's pretty clear that is Who is being discussed, whereas the MOA only gets you as far as a deistic god.
I also take exception to Plantinga's use of the term "God". Christianity is the only religion that refers to their deity in this way, so it's pretty clear that is Who is being discussed, whereas the MOA only gets you as far as a deistic god.