One of the interesting things about some theists is that they assume a kind of binary set-up. That is, if you are not satisfied with arguments for theism, you have to suggest your own version of reality. But this is not correct. Apart from reversing the burden of proof, it also suggests that arguments for theism are only deficient, if other arguments for another type of reality are presented. Not so.
Take the beginning of the universe. If X says he is not satisfied with the idea that God did it, X is not obliged to suggest another idea. He could say, I don't know, and this doesn't disqualify him from pointing to the deficiencies of the creationist version.
But this black and white thinking is quite common on the internet - you can't criticize me, unless you have an alternative theory. Of course, it's a familiar way of avoiding the gaps in one's own arguments.