One of the things that always bothered me about the "Big Bang" was the mathematically awkward descriptions of the setoff process. This was alleviated for me somewhat by the newish assertion that the universe quantum tunnelled itself into existence. This takes care of the issue about what there was before by answering "nothing". The problem that it created however (to me) was that A) since there is no visible "antimatter" balancing the matter, there seems a distinct breaking of fundamental rules of some kind and B) What is stopping a big bang happening within our universe at any time to wreck it?. Matter and anti-matter pairs are constantly coming and going out of existence in the vaccuum of space, as far as I know, with no discernible other effects.
My theory is that if our universe and an antimatter copy of our universe were travelling away from eachother at the speed of light, that would resolve requirements of self-consistency of laws of conservation of matter/energy. Infact, one could postulate an infinite number of universes all travelling away from eachother at the speed of light, in matter/antimatter pairs. That would account for the infinite parallel universes that yet other theoretical scientists postulate, and explain why we can't see them.