Razor & Blade Combos?

[Mr. O]

I keep reading how blade x performs better in razor y and blade z doesn't perform at all in razor y etc. So I have a three part question. The first, why do some razors perform better with certain blades and not others? And secondly, what combos of razors & blades have you found work the best with each other? And lastly, what possible reasons can you think of for successful razor & blade combos.