Very nice hotels for €100 in downtown areas that would cost easily $300/night in USA. Food in restaurants and cafes very reasonably priced, I got a couple coffees and pastries for like €8 and the coffee alone would be that much in the states let alone multiple pastries. €5 felafel. I can’t remember the last time I paid less than $15 for lunch.
Gas is super pricey but who cares when your cities are designed to be walkable and you have great public transport everywhere.
I get that I’m on the tourist route so this doesn’t represent true cost of living, but I understand rent is far cheaper in general, plus availability of healthcare and education leads me to believe COL in general is lower and some googling supports this.
I don’t know anything about their tax policies so I can’t comment on that either.