Just how much %cash back is a mile worth for you?(Country specific: US/UK/German/etc)
I know, I know. You have all those special deals with miles that you can't have with cash back and everyone have their own preferences.
But really, if you have to convert one to the other, what is your exchange rate?
Of course, you have different options with each country. Can you have a 3% cash on ALL products or 2% is the maximum?