Belgium is pretty fair. NL requires you to pay between 100 and 150 euros per month or so (kids are free) and that covers everything, the rest is paid from the tax base so you already pay the income dependent part. The only bit that's nasty about it is the deductible, they really screw the poor people on that because of course only the cheap plans have high deductibles so those that can afford the least will end up with the highest costs when something does go wrong.
In Belgium, you are charged based on your income, and they don't ask you how much you can pay when you get admitted.
As US ex-pats, we made enough money that we were in the top payment bracket.
Yet, for a significant surgery that kept my wife in the hospital in a private room for two weeks, we still paid less for the whole surgery plus hospital room WITHOUT insurance, than we would have paid in the US but with insurance.
That kind of social medicine does actually work, and work pretty well.