The problem with predestination is this: there ends up being one will in the universe. This gets confusing, because of all the people that believe, for instance, that the young lady in Florida currently being starved to death is against the will of God, but have to believe, doctrinally, that it is at the same time in accord with God’s will.
I get a headache just thinking about it.
In dealing with the predestination statements in Scripture, C. S. Lewis wrote to the effect that humans always get turned around when they speak of a being that has its existence outside time and mortality. There’s no way to discuss it without getting confused.
I was compelled to learn about Catholicism because of two things — G. K. Chesterton (he was fat and smoked cigars — I resonate with that!) and the teaching of predestination. So, if I were you RC’s, I’d keep my objections to predestination to yourselves, because it might be sending many reformed churchpeople your way!