In the us they might have more money (to then spend on healrhcare etc)
Which is “better”?
If you’re below the average (income/wealth wise) and have other disadvantages you might certainly be better off in Europe. Otherwise (inherited wealth aside) US might be a better place to be depending on your personal preferences and priorities.
The transit is trash anywhere that you can actually afford to own property. The healthcare outcomes you mentioned are going to need a citation because the middle class in the US generally has OK insurance.
For happiness, that’s vague and will need a citation. Putting the entire US on a comparison with individual EU countries is dumb, but that’s how it’s sliced in https://en.wikipedia.org/wiki/World_Happiness_Report where the US is beat by many EU countries and beats others (e.g. Spain and Italy).
> Which is “better”?
Probably the one with the most immigration.