I've never used any of these products before but my basic understanding is that it doesn't really replace the cycling process, it just helps it a long. You add this product and usually do it for a few days and then add fish. It seems like the reality is you are in the end just doing a fish in cycle because the cycle doesn't actually start until you add an ammonia source.
Though it's one of those things people will fight over. Some swear by it and others claim it's useless.
Personally I'd save my money and try to purchase some seeded media instead. At least you know for sure this will work.
By chemicals what do you mean? If you are cycling fishless then you just need a liquid test kit and ammonia. If you mean once you have fish.. really I think a good water conditioner like Prime.
