When it comes right down to it, whether you are Calvinist or Arminian, God knows exactly who is going to be saved, and no one else other than this group will be saved. And, the number won't vary whatsoever.
God has perfect, exhaustive foreknowledge and knows the number and the names.
Only open theists would claim otherwise, and their position is plainly unbiblical (Isaiah 46:9-10).
So, in a sense, the fate of the individual who is born has already been decided, and nothing is going to change that. For some people, the minute they are born, they are hopeless because God knows they are not in the elect. For the rest, they are never going to be hopeless because they are one of the elect.
There is no escaping this, unless you claim God's knowledge is limited, and that he lives life in sequence like man does. This is a sub-Christian view. I used to have an open-theist view due to the sub-Christian cult I belonged to. I was told that God didn't even know I was going to exist until I was conceived and born. Their god was after their own imagination.
The difference is WHY the person is saved. Reformed theology believes salvation is totally by grace, and that God regenerates the person prior to salvation. This regeneration causes the spiritually dead person to be reborn, giving them a new spiritual nature that wants to obey and love God. He therefore places his faith in Jesus Christ and repents due to this change in nature. It is totally by grace, and God is the author and finisher of that person's salvation. And, regardless of who he elects, they WILL be saved despite whatever circumstances that person faces in regards to their environment..God WILL accomplish his purpose in this person.
Arminian or synergistic believers think that God brings the person to a state of "prevenient grace" (the Scotch tape of Arminian theology which has no biblical basis) so that the spiritually dead person is in a semi-comatose state where they are able to choose God or to reject him...neither fully alive nor fully dead. If the person decides to respond in faith, they are saved and regenerated (after salvation). If the person decides not to respond, God apparently continues to woo them like a jilted, helpless boyfriend until they eventually respond or he decides to give up (as if he didn't know the outcome anyways). There's no consensus on whether God provides an equal playing field for this person, or how long he tries until he gives up (as if he doesn't know it's hopeless when he starts).
Some will say, it's not fair if God chooses. The fair thing is that we all go to eternal punishment. The fact that he saves anyone is totally grace. Westerners think that everyone has a RIGHT to the same opportunity...I would contest that.
I also think that if God elects as Reformed theology teaches, it's actually MORE FAIR for some individuals. For instance, it's not fair if some guy in Saudi Arabia is born into a family who is Muslim and he was raised being a Christ-hater, if equal opportunity is an entitlement to all individuals, versus myself who was raised in a home with a Christian parent and exposed to some level of an understanding and bias toward Christianity. Through election, God ensures that the Muslim he elects comes to faith regardless of his circumstances..there is no doubt that this Muslim will be saved, no matter if it requires special dreams or extraordinary means, if God has ordained it.
To buy into the Arminian view, one has to believe that God, who knows the hearts of all men, cannot accomplish his will in that person's life if he chooses to do so. I simply reject that view based on God's omniscience and omnipotence. If he has to go to extraordinary means, he can accomplish salvation in anyone, therefore I must believe that he is passing over the ones which are not saved. Look at Nebuchadnezzar and Paul as examples. I don't think they would have been in the yearbook under "Most Likely to be Saved" yet both responded to God, praising Him ultimately. Nebuchadnezzar was reduced to the status of a grass-eating creature in order to do it, and Paul was knocked off his donkey and blinded to accomplish it.
Anyways, Reformed theology is the most coherent view exegetically. I wouldn't even consider returning back to Arminian theology.
I would also ask non-Reformed people..given their theology, how much effort does God expend in bringing someone to salvation before he gives up? Why does he expend any effort if he already knows the outcome? Do you seriously think the Midianite high priest had the same opportunity to know God as Moses?
Ultimately, I think the Arminian is faced with the issue of his salvation being attributed, at least in part, to his own personal merit. I don't think he can escape that ultimate conclusion. There was something superior to me that caused me to place my faith in Jesus, versus the guy who did not, so there is SOMETHING to boast about. I was wiser than the other guy who failed to do so. I don't think personal merit can be removed from the equation in an Arminian worldview.