What do you think of this argument for God?

[Nonpareil]

I'm afraid, that if you do not understand what "all knowing" or "all powerful" is, then I don't believe I can simplify those any more for you.

You misunderstand.

It is not that there is no understandable concept. It is that there is no working definition. In the same way, while the concept of "soul" is understandable, no actual working definition can be supplied. No mechanism or definitive limits and parameters can be given.

And they desperately need that, because without it, it can easily be argued that such properties are not possible, even speaking metaphysically - or, if you wish to be more generous, you could posit that they are possible, but incompatible due to omniscience and its interaction with the idea of free will or choice, or omnipotence and its interaction with concepts of logical possibility and coherence. And so on.

That's the problem with concepts like these. They've been around so long, and appear so simple, that people just sort of take it as written that they are coherently defined.

But if you are saying that nothing is objectively greater than anything else, then I disagree and find it absurd.  You are saying that knowledge is not greater than ignorance, and wisdom is not greater than foolishness.   That these are incoherent statements correct?  That these are just value judgements?

Incoherent, no. Value judgments, and therefore subjective, yes.

Systems of measuring value can be defined, and certain properties can be compared to those systems to find that they are more valuable, by that standard, than another property. But the key phrase is that this can be done by that standard. There is no objective measurement of value possible, and the concept of a "maximum value" is nonsensical.

Correct me if I'm wrong, but you appear to be saying here, that under the axioms of S5, that it must be shown epistemically possible in the actual world.  Now I'm just learning this stuff myself, but nothing I see, in the descriptions of S5 state this. Why have the semantics of other possible worlds at all, if this where true.

Again, I'm not a particular expert on modal logic myself. I could be entirely wrong, which is why I continue to point this out. I am continuing to read up on this, and, as I have said, this is not a particularly concrete conclusion on my part. I am currently working my way through - in my free time, which is why I don't have a more definitive answer - the various publications of Robert Stalnaker, who talks about exactly this issue. Specifically, I'm looking at "Propositions" and "Possible Worlds", which you can find on Google.

As a reminder, though, even if my admitted speculation was entirely wrong, it still doesn't actually help the ontological argument -

Now as discussed the argument does leave open the possibility that God is not logically possible.

For exactly that reason.

In addition to the above issues with needing a coherent definition for the various characteristics of God, the ontological argument fails to show that it is possible for an entity that is "maximally excellent" to have necessary existence in every possible world. As it is logically coherent to posit that there is a possible world where no entity possesses maximal excellence, this would not appear to be the case.
 

However as I stated; I tend to default to possible rather than impossible, if I do not find a reason to do so.

You are free to do so, but if you want to be rational about it, that is exactly the opposite of what should be done.

Possibility must be established, not merely assumed. As such, a coherent definition must be supplied, and a demonstration of how this definition is compatible with the universe must be made.